Acronym Dictionary

2D – 2-Dimensional

3D – 3-Dimensional

3M – Minnesota Mining and Manufacturing

4GL – Fourth Generation Language

4H – Head, Heart, Hands, Health

4WD – Four wheel Drive (see also FWD)

A – Aftermath

AA – Affirmative Action committee

AA – Alcoholics Anonymous

AA – Antiaircraft Artillery

AA – Associate in Accounting

A&A – Astronomy and Astrophysics [Space]

AA – Automobile Association [England]

AAA – American Automobile Association

AAAL – American Academy of Arts and Letters

AAAS – American Association for the Advancement of Science

AAII – American Association of Individual Investors

AAMSI – American Association for Medical Systems Informatics

AAO – Anglo-Australian Observatory [Space]

AAP – Affirmative Action Program

AARC – Anglo-American Cataloging Rules

AARN – Australian Academic Research Network [Networking]

AARP – American Association of Retired Persons

AAS – American Astronomical Society [Space]

AAVSO – American Association of Variable Star Observers [Space]

AB – ABle seaman

ABA – American Bar Association

ABA – American Basketball Association

ABA – American Booksellers Association

ABBR – ABBReviation

ABC – American Broadcasting Company [Corporate name]

AC – Alternating Current (ac, see also DC)

AC – Ante Christum (before Christ)

AC – Ante Cibum (before meals)

ACAA – Agricultural Conservation and Adjustment Administration

ACAWS – Advisory, Caution, And Warning System

ACBL – American Contract Bridge League

ACC – Argonne Code Center

ACCS – Army Command and Control System

ACD – Automatic Call Distributor [Telephony]

ACE – Advanced Composition Explorer [Space]

ACE – Advanced Computing Environments [Corporate name]

ACE – Automatic Calibration and Equalization

ACHEFT – Automated ClearingHouse Electronic Funds Transfer

ACK – ACKnowledge

ACL – Advanced Cmos Logic

ACLU – American Civil Liberties Union

ACM – Association for Computing Machinery

ACRV – Assured Crew Return Vehicle (or) Astronaut Crew Rescue Vehicle [Space]

ACS – Advanced Communications System

ACSE – Association Control Service Entity (ISO/CCITT layer 7)

ACT – Action for Children’s Television (in Cambridge, MA)

ACT – American Conservatory Theater

ACTS – Advanced Communications Technology Satellite

ACTS – Automatic Coin Telephone Service [Telephony]

ACU – Alarm Control Unit

ACU – Automatic Call Unit [Telephony]

ACW – Alternating Continuous Waves

AD – After Date

A/D – Analog to Digital converter (see ADC)

AD – Anno Domini (in the year of our Lord)

AD – Application Development

ADAP – Alzheimer’s disease-associated protein

ADAP – American Discount Auto Parts [Corporate name]

ADB – A DeBugger

ADB – Apple Desktop Bus

ADC – Analog to Digital Converter

ADCI – Automatic Display Call Indicator

AD&D – Advanced Dungeons & Dragons

ADF – Automatic Direction Finder

ADM – ADMiral

ADP – Adenosine Di-Phosphate

ADP – Administrative Data Processing

ADP – Advanced Data Processing

ADPCM – Pulse Code Modulation with Adaptive Quantization

ADS – Application Development System

ADSR – Attack Decay Sustain Release

ADT – Abstract Data Type

ADT – Atlantic Daylight Time

AE – Application Execution

AEA – American Electronics Association

AEC – Atomic Energy Commission

AEF – American Expeditionary Force (see BEF)

AEGIS – Advanced Electronic Guidance and Instrumentation System

AF – Adventures in Fantasy

AF – Air Force

AF – Audio Frequency

AFADS – Automatic Force Adjustment Data System

AFATDS – Advanced Field Artillery Tactical Data System

AFB – Air Force Base

AFC – American Football Conference

AFC – Automatic Flight Control

AFC – Automatic Frequency Control

AFCAC – Air Force Computer Acquisition Center

AFCC – Air Force Communications Command

AFGE – American Federation of Government Employees

AFIPS – American Federation of Information Processing Societies

AFL – American Federation of Labor

AFL – American Football League

AFLCIO – American Federation of Labor and Congress of Industrial Organizations

AFNOR – Association Francaise de NORmalization

AFP – Appletalk Filing Protocol

AFS – Andrew File System

AFSC – Air Force Systems Command

AFSCME – American Federation of State, County and Municipal Employees

AFTRA – American Federation of Television and Radio Artists

AG – Adjutant General

AG – Arcade Game

AG – Attorney General

AGCT – Army General Classification Test

AGN – Active Galactic Nucleus [Space]

AHL – American Hockey League

AHQ – Air HeadQuarters

AI – Artificial Intelligence

AIAA – American Institute of Aeronautics and Astronautics [Space]

AIC – Automatic Intercept Center

AID – Agency for International Development

AIDDE – Ames’ Interactive Dynamic Display Editor

AIDS – Acquired ImmunoDeficiency Syndrome

AIOD – Automatic Identification Outward Dialing

AIS – Automatic Intercept System

AIX – Advanced Interactive eXecutive (IBM’s name for UNIX)

AJ – Astronomical Journal [Space]

AK – Alaska

AKA – Also Known As

AL – Alabama [US state postal designation]

AL – American League (baseball)

ALA – American Library Association

ALA – Automobile Legal Association

ALBM – Air-to-Land Ballistic Missile

ALC – Automatic Load Control

ALGOL – ALGOrithmic Language

ALIT – Automatic Line Insulation Testing [Telephony]

ALPO – Association of Lunar and Planetary Observers [Space]

ALS – Advanced Launch System [Space]

ALU – Arithmetic Logic Unit

A&M – Agricultural and Mechanical

AM – Amplitude Modulation

AM – Ante Meridiem (before noon)

AMA – American Medical Association

AMA – Automatic Message Accounting [Telephony]

AMARC – Automatic Message Accounting Recording Center

AMBA – Association of Master of Business Administration

AMC – Albany Medical College

AMC – American Motors Corporation(?) [Corporate name]

AMC – Appalachian Mountain Club

AMD – Advanced Micro Devices [Corporate name]

AMEX – AMerican EXpress [Corporate name]

AMI – Alternate Mark Inversion (see also NRZ, NRZI, B8ZS)

AMORC – Ancient Mystic Order Rosae Crucis

AMP – Adenosine MonoPhosphate

AMPAS – Academy of Motion Picture Arts and Sciences

AMPAS – Acedemy of Motion Picture Arts and Sciences

AMRAAM – Advanced Medium Range Air-To-Air Missile

AMROC – American Rocket Company [Space]

AMSAT – radio AMateur SATellite corp.

AMU – Atomic Mass Unit

AMVET – AMerican VETeran

ANA – American Nurses Association

ANAC – Automatic Number Announcemnt Circuit [Telephony]

ANC – All Number Calling [Telephony]

ANC – Army Nurse Corps

ANDF – Architecture-Neural Distribution Format

ANF – Automatic Number Forwarding [Telephony]

ANG – Air National Guard

ANI – Automatic Number Identification (see also: CLID) [Telephony]

ANL – Argonne National Laboratory

ANOVA – ANalysis Of VAriance

ANPA – American Newspaper Publishers Association

ANSI – American National Standards Institute

ANZUS – Australia, New Zealand, United States

AO – Account Of

AOA – Abort Once Around [NASA, Shuttle]

AOA – Abort Once Around (Shuttle abort plan) [Space]

AOL – Absent Over Leave (see AWOL)

AOS – Academic Operating System

AOS – Alternate Operator Service [Telephony]

A/P – Accounts Payable

AP – Additional Premium

AP – All Points

AP – Associated Press [Corporate name]

APA – All Points Addressable

APA – American Psychological Association

APB – All Points Bulletin

APDA – Apple Programmers and Developers Association

API – Application Programming Interface

APICS – American Production and Inventory Control Society

Ap.J – Astrophysical Journal [Space]

APL – A Programming Language

APL – acute promyelocytic leukemia [Disease]

APO – Alpha Phi Omega, service fraternity

APO – Army Post Office

APP – Applications Portability Profile

APPC – Advanced Peer-to-Peer Communications

APR – Annual Percentage Rate (as in loan interest)

APSE – Ada Programming Support Environment

APU – Auxiliary Power Unit [Space]

AQ – Accumulator-Quotient register

A/R – Accounts Receivable

AR – Address Register

AR – Arkansas

ARC – AIDS-related complex

ARC – American Red Cross

ARC – Ames Research Center (NASA) [Space]

ARCNET – Attached Resource Computer local area NETwork

ARO – After Receipt of Order

ARP – Address Resolution Protocol

ARPA – Advanced Research Projects Agency (of the DoD, see DARPA)

ARPANET ARPA (q.v.) NETwork

ARRL – Amateur Radio Relay League

ARV – American Revised Version

AS – Anglo-Saxon

ASA – Acetyl Salicylic Acid

ASAP – As Soon As Possible

ASC – Accredited Standards Committee

ASCAP – American Society of Composers, Authors, and Publishers

ASCC – Automatic Sequence-Controlled Calculator

ASCII – American Standard Code for Information Interchange

ASDIC – Anti-Submarine Detection Investigation Committee (British for sonar)

ASDSP – Application-Specific Digital Signal Processor

ASG – Automated Sciences Group

ASHRAE – Amer. Soc. of Heating, Refrigerating and Air-cond. Engineers, inc.

ASIC – Application Specific Integrated Circuit

ASME – American Society of Mechanical Engineers

ASN – Abstract Syntax Notation One (ISO/CCITT ASN.1)

ASP – Aggregated Switch Procurement

ASRM – Advanced Solid Rocket Motor [Space]

ASSR – Autonomous Soviet Socialist Republic

AST – Atlantic Standard Time

ASV – American Standard Version

AT – Atlantic Time

ATA – Automatic Trouble Analysis

ATACC – Advanced Tactical Air Command Central

ATB – Advanced Technology Bomber (stealth bomber)

ATC – Air Traffic Control

ATDRS – Advanced Tracking and Data Relay Satellite [Space]

ATF – Advanced Technology Fighter

ATIS – Atherton Tools Interface Specification

ATLAS – Atmospheric Laboratory for Applications and Science [Space]

ATM – Amateur Telescope Maker [Space]

ATM – Asynchronous Transfer Mode

ATM – Automatic Teller Machine

ATO – Abort To Orbit [NASA, Shuttle]

ATO – Abort To Orbit (Shuttle abort plan) [Space]

ATOMS – AT&t Optimized Materials Simulator

ATP – Adenosine TriPhosphate

ATPCO – Airline Tariff Publishing COmpany

AT&T – American Telephone & Telegraph [Corporate name]

ATT – American Telephone & Telegraph (normally written AT&T when seperate)

ATTIS – American Telephone and Telegraph Information Systems [AT&T] (Division)

ATV – All Terrain Vehicle

AU – Astronomical Unit (93,000,000 miles) [Space]

AU – Astronomical Unit [Space]

AUI – Attachment Universal Interface

AURA – Association of Universities for Research in Astronomy [Space]

AUS – Army of the United States

AUTODIN AUTOmatic DIgital Network

AUTOVON AUTOmatic VOice Network

AV – AudioVisual

AVLIS – Atomic Vapor Laser Isotope Separation

AWACS – Airborne Warnings And Control Systems

AWEA – American Wind Energy Association

AWK – al Aho, peter Weinberger, brian Kernighan (pattern scanning language)

AWOL – Absent WithOut Leave (also Absent Without Official Leave) (see AOL)

AW&ST – Aviation Week and Space Technology (a.k.a. AvLeak) [Space]

AXAF – Advanced X-ray Astrophysics Facility [Space]

AZ – Arizona

B – Book

B8ZS – Binary 8 Zero Substitution (see also NRZ, NRZI, AMI)

BA – Bachelor of Arts

BACH – Business Alliance for Commerce in Hemp

BAFO – Best And Final Offer

BARRNet Bay Area Regional Research Network (SF Bay Area)

BASIC – Beginner’s All-purpose Symbolic Instruction Code

BATSE – Burst And Transient Source Experiment (on GRO) [Space]

BB – Bases on Balls

BB – Best of Breed

BB – Bunnies and Burrows

BBA – Bachelor of Business Administration

BBB – Better Business Bureau

BBC – British Broadcasting Corporation

BBL – Barrel

BBN – Bolt, Beranek, and Newman, Inc. [Corporate name]

BBXRT – Broad-Band X-Ray Telescope (ASTRO package) [Space]

BC – Battlecars

BC – Before Christ

BC – British Columbia

BC/BS – Blue Cross/Blue Shield

BCD – Bad Conduct Discharge

BCD – Binary Coded Decimal

BCDIC – Binary Coded Decimal Interchange Code

BCE – Before the Common Era (substitute for BC)

BCNU – Be Seeing You [Net jargon]

BCP – Byte Controlled Protocols

BCPL – Basic Combined Programming Language

BCS – Bachelor of Commercial Science

BCS – Binary Compatibility Standard

BCS – Boston Computer Society

BCS – British Computer Society

BD – Bachelor of Divinity

BD – Bank Draft

BD – Bills Discounted

BD&D – Basic Dungeons & Dragons

BDF – Binary Distribution Format

BDT – Billing Data Transmitter

BE – Bill of Exchange

BEF – British Expeditionary Force (see AEF)

BELCORE BELL COmmunications REsearch

BEM – Bug Eyed Monster

BEM – Bug-Eyed Monster [Space]

BENELUX BElgium, NEtherlands, and LUXembourg

BER – Bit Error Rate

BERT – Bit Error Rate Test

BEST – Borland Enhanced Support and Training

BF – Brought Forward

BFA – Bachelor of Fine Arts

BFD – Bristol (RI) Fire Department (probably typical of any town starting “B”)

BH – Black Hole [Space]

BH – Boot Hill

BHP – Brake HorsePower

BICS – Building Industry Consulting Services [Telephony]

BID – Bis In Die (twice a day)

BIMA – Berkeley Illinois Maryland Array [Space]

BIOS – Basic Input Output System

BIS – Business Information System

BISDN – Broadband ISDN (q.v.) [Telephony]

BiSync – Binary Synchronous Communications (BSC is preferred) [IBM]

Bit – BInary digiT

BITNET – Because It’s Time Network

BLAST – BLocked ASynchronous Transmission

BLERT – BLock Error Rate Test

BLF – Busy Lamp Field [Telephony]

BLT – Bacon, Lettuce, and Tomato (sandwich)

BLT – BLock Transfer [Instruction]

BLT – Branch Less Than [Instruction]

BM – Basal Metabolism

BM – Bowel Movement

BMA – Bank Marketing Association

BMEWS – Ballistic Missile Early Warning

BMO – Ballistic Missile Office

BMOC – Big Man On Campus

BMR – Basal Metabolism Rate

BNC – Bayonet Neill Concelman (connector) [Electronics] (see also TNC)

BNF – Bachus-Naur Form

BO – Body Odor

BO – Branch Office

BO – Buyer’s Option

BOC – Bell Operating Company

BOD – Board Of Directors

BOF – Birds Of a Feather

BOM – Bill Of Materials

BOOTP – Bootstrap Protocol [Internet]

BOQ – Bachelor Officers’ Quarters

BOS – Business Office Supervisor

BOSIX – Biin Open System Interface eXtension

BP – Blood Pressure

BP – British Petroleum

BP – British Pharmacopoeia

BPI – Bits Per Inch

BPL – Boston Public Library

BPL – Branch if PLus [Instruction]

BPOE – Benevolent and Protective Order of Elks

BPS – Bits Per Second

BR – Bills Receivable

BR – British Rail

BRA – Boston Redevelopment Authority

BRI – Basic Rate Interface (ISDN) [Telephony]

BRIEF – Basic Reconfigurable Interactive Editing Facility

BRL – army Ballistic Research Laboratory

BRS – Bibliographic Retrieval Service

BS – Bachelor of Science

BS – Bill of Sale

BSA – Birmingham Small Arms

BSA – Boy Scouts of America

BSc – Bachelor of SCience

BSC – Binary Synchronous Communications (also sometimes BiSync) [IBM]

BSD – Berkeley Software Distribution

BSN – Bachelor of Science in Nursing

BSS – Block Started by Symbol

BSTJ – Bell System Technical Journal

BT – British Telecom

BTAM – Basic Telecommunications Access Method [IBM]

BThU – British Thermal Unit (BTU {q.v.} is preferred)

BTL – Bell Telephone Laboratories

BTO – Bachman Turner Overdrive

BTU – British Thermal Unit

BTW – By The Way [Net jargon]

BU – Boston University

BUF – B-52 bomber (“Big Ugly Fellow”) [USAF]

BV – Blessed Virgin

BWI – Baltimore-Washington International (airport)

BWI – British West Indies

BX – Base eXchange (see also PX)

c – centi- (metric 1/100)

C – programming language (successor to B, which was based on BCPL)

CA – California

CA – Chartered Accountant

CA – Chief Accountant

CA – Chronological Age

CA – Collision Avoidance (as in CSMA/CA (q.v.))

CAB – Civil Aeronautics Board

CACM – Communications of the Association for Computing Machinery

CAD – Computer Aided Design (sometimes seen as CAD/CAM)

CAD – Computer Aided Dispatching

CAE – Common Applications Environment

CAE – Computer Aided Engineering

CAI – Computer Aided Instruction

CAIS – Common Apse Interface Specification

CALS – Computer-aided Acquisition and Logistics Support

CAM – Computer Aided Management

CAM – Computer Aided Manufacturing (sometimes seen as CAD/CAM)

CAM – Content Addressable Memory

CAMA – Centralized Automatic Message Accounting [Telephony]

CAMP – Campaign Against Marijuana Planting

CAP – Civil Air Patrol

CAP – Columbia Appletalk Package

CAR – Contents of the Address part of the Register (LISP)

CARE – Committee on American Relief in Europe

CARP – California Air Resources Board

CASE – Computer Aided Software Engineering

CASSIS – Classification and Search Support Information System

CAT – Computer-Aided Tomography

CATIS – Common Applications and Tools Integration Services

CATV – Common Antenna TeleVision

CATV – Community Antenna TeleVision

CAVU – Ceiling And Visibility Unlimited

CB – Citizens Band radio

CBC – Canadian Broadcasting Corporation

CBD – Cash Before Delivery

CBD – Commerce Business Daily

CBEMA – Computer & Business Equipment Manufacturers Association

CBR – Chemical, Biological, Radiological warfare

CBS – Columbia Broadcasting System [Corporate name]

CBW – Chemical and Biological Warfare

CC – C (language) Compiler

CC – Carbon Copy

CCA – Computer Corporation of America [Corporate name]

CCAFS – Cape Canaveral Air Force Station [Space]

CCC – Canadian Committee on Cataloging

CCC – Civil(ian) Conservation Corps

CCC – Command, Control, and Communications (sometimes C^3)

CCC – Concourse Computer Center [MIT]

CCCCM – CCC CounterMeasures (sometimes C^3CM)

CCCI – Command, Control, Communications, and Intelligence

CCD – Charge Coupled Device (see CID)

CCD – Charge-Coupled Device [Space]

CCDS – Centers for the Commercial Development of Space [Space]

CCF – Hundred Cubic Feet

CCI – Computer Carrier Interrupt

CCI – Computer Consoles, Incorporated

CCIP – Continuously Computed Impact Point

CCIRN – Coordinating Committee for Intercontinental Research Networking

CCIS – Common Channel Interoffice Signaling [Telephony]

CCITT – Comite’ Consultatif International Telegraphique et Telephonique

CCITT – Consultative Committee on International Telephony and Telegraphy

CCITT – International Telegraph and Telephone Consultative Committee

CCR – Commitment, Concurrency, and Recovery

CCR – Creedence Clearwater Revival [Music]

CCRI – Community College of Rhode Island [Corporate name]

CCRP – Continuously Computed Release Point

CCS – Hundred Call Seconds [Telephony]

CCS7 – Common Channel Signalling (version #7) [Telephony, AT&T]

CCSA – Common Control Switching Arrangement [Telephony]

CCTA – Central Computer and Telecommunications Agency

CCTV – Closed Circuit TeleVision

CD – Carrier Detect (properly DCD (q.v.)) (EIA RS-232-C)

CD – Certificate of Deposit

CD – Civil Defense

CD – Collision Detection (as in CSMA/CD (q.v.))

CD – Compact Disk

CDA – Call Data Accumulator

CDA – Compound Documents Architecture

CDC – Centers for Disease Control

CDC – Control Data Corporation, Inc. [Corporate name]

CDEV – Control panel DEVice

CDIAC – Carbon Dioxide Information Analysis Center

CDO – Community Dial Office

CDR – CommanDeR

CDR – Contents of the Decrement part of the Register (LISP)

CD-ROM – Compact Disk Read Only Memory

CD-ROM – Compact Disk Read-Only Memory [Space]

CDSF – Commercially Developed Space Facility

CDT – Central Daylight Time

CDU – Control Display Unit

CE – Chemical Engineer

CE – Civil Engineer

CE – Common Era (substitute for AD)

CE – Corps of Engineers

CE – Customer Engineer (see also FE, SE)

CEA – Commissariat a l’Energie Atomique (Frenc Atomic Energy Commision)

CEA – Council of Economic Advisors

CEA – County Education Authority

CEC – Commission of the European Communities

CED – Committee for Economic Development

CELSS – Controlled Ecological Life Support System [Space]

CENS – Centre d’Etudes Nucleaires de Seclay

CENTO – CENtral Treaty Organization

CEO – Chief Executive Officer

CERFnet California Education and Research Federation Network

CERN – European Organization for Nuclear Research

CERN – organisation (formerly Conseil) Europeenne pour la Recherche Nucleaires

CERT – Computer Emergency Response Team

CEVI – Common Equipment Voltage Indicator

CF – Carry Forward

CF – Coin First (payphone) [Telephony]

CF – Cystic Fibrosis [Disease]

CFA – Center For Astrophysics [Space]

CFC – Chloro-FluoroCarbon [Chemical]

CFC – Combined Federal Campaign

CFD – Computational Fluid Dynamics

CFHT – Canada-France-Hawaii Telescope [Space]

CFI – Cost, Freight, and Insurance

CFL – Canadian Football League

CFO – Chief Financial Officer

CG – Coast Guard

CG – Commanding General

CGA – Color Graphics Adapter

CGCT – Compagnie Generale de Constructions Telephoniques

CG&E – Cincinnati Gas & Electric

CGE – Compagnie Generale d’Electricite

CH – Cardboard Heroes

CH – ClearingHouse

CH – CourtHouse

CH – Customs House

CHA – Champions

CHAP – CHAnnel Processor

CHARA – Center for High Angular Resolution Astronomy [Space]

CHI – Chill: – Adventures into the Unknown

CHOTS – Corporate Headquarters Office Technology System

CHP – California Highway Patrol

CI – Cubic Inches

CIA – Central Intelligence Agency [US Government]

CIA – Culinary Institute of America (Hyde Park, NY)

CIC – Carrier Identification Codes [Telephony] (10XXX codes)

CIC – Committee on Institutional Cooperation

CIC – Coordination and Information Center [CSNet]

CICA – Competition in Contracting Act

CICS – Customer Information Control System [IBM]

CID – Caller ID [Telephony] (see also: CLID, ANI)

CID – Central Institute for the Deaf

CID – Charge Injection Device (see CCD)

CID – Computer Integrated Design

CIDIN – Common Icao Data Interchange Network

CIM – Computer Integrated Manufacturing

CIO – Chief Information Officer

CIRRIS – Cryogenic InfraRed Radiance Instrument for Shuttle [Space]

CISC – Complex Instruction Set Computer

CIT – California Institute of Technology

CIT – Case Institute of Technology (part of CWRU, Cleveland, OH)

CIT – Circumstellar Imaging Telescope [Space]

CLASP – Comprehensive Logistics Automated Support Program

CLASS – Custom Local Area Signaling Service [Telephony]

CLI – Command Line Interpreter

CLID – Calling Line ID [Telephony] (see also: CID, ANI)

CLNP – Connectionless-mode Network Protocol

CLNS – Connectionless-mode Network Service

CLR – Combined Line and Recording

CLRC – Circuit Layout Record Card

CLU – Chartered Life Underwriter

CLUT – Color LookUp Table

cm – centimeters

CM – Command Module (Apollo spacecraft) [Space]

CM – Congregation of the Mission

CMC – Communication Machinery Corp.

CMD – Centralized Message Distribution

CMIP – Common Management Information Protocol

CMIS – Common Management Information Services

CML – Current Model Logic

CMMU – Cache/Memory Management Unit

CMOS – Complementary Metal Oxide Semiconductor (see MOS)

CMOT – Common Management Information Services and Protocol Over TCP/IP

CMRR – Common Mode Rejection Ratio

CMS – Circuit Maintenance System

CMSgt – Chief Master Sergeant

CMU – Carnegie-Mellon University

CMYK – Cyan, Magenta, Yellow, blacK

CN – Canadian National [Corporate name, Railroading]

CN/A – Customer Name / Address [Telephony]

CNI – Common Network Interface [Telephony, AT&T] (Department of AT&T)

CNN – Cable News Network

CNO – Carbon-Nitrogen-Oxygen [Space]

CNO – Chief of Naval Operations

CNR – Canadian National Railways

CNR – Carrier to Noise Ratio

CNRI – Corporation for National Research Initiatives

CNRS – Centre National de la Recherche Scientifique (French National Center for Scientific Research)

CNS – Central Nervous System

CNSR – Comet Nucleus Sample Return [Space]

CO – Cash Order

CO – Central Office [Telephony]

CO – Colorado

CO – Commanding Officer

CO – Conscientious Objector

C/O – in Care Of

COB – Close Of Business

COBE – COsmic Background Explorer [Space]

COBOL – COmmon Business Oriented Language

COC – Call of Cthulhu

COCOT – Customer Owned, Coin Operated Telephone [Telephony]

COD – Collect On Delivery; Cash On Delivery

CODEC – COder-DECoder

COER – Central Office Equipment Report

COLA – Cost-Of-Living Allowance

COM – Computer Output (on) Microfiche

COM – Computer Output (on) Microfilm

COMAS – Central Office Maintenance and Administration System

COMM – Communications

COMPACT COMmercial Product ACquisition Team

COMPTEL COMPton TELescope (on GRO) [Space]

COMSAT – Communications Satellite [Space]

CONACYT Consejo Nacional de Cienca Y Tecnologia (Mexican National Council of Science and Technology)

CONS – Connection-Oriented Networking Service

CONS – Connection-Oriented Networking Session

CONS – CONStruct (LISP)

CORE – COntrolled Requirement Expression

CORN – COmputer Resource Nucleus

COS – Corporation for Open Systems

COSINE – Cooperation for Open Systems Interconnection Networking in Europe

COSMIC – COmmon System Main InterConnecting frame

COSMIC – COmputer Software Management and Information Center

COSMOS – COmputer System for Mainframe OperationS

COSTAR – Corrective Optics Space Telescope Axial Replacement [Space]

COT – Card Or Tape (NCR)

CP – Campus Police (MIT, others probably too)

CP – Canadian Pacific

CP – Chemically Pure

CP – Command Post

CP – Command Processor

CP – CoPy

CP – the Canadian Press

CPA – Certified Public Accountant

CPE – Customer Premises Equipment

CPE – Customer Provided Equipment

CPFF – Cost Plus Fixed Fee

CPI – Characters Per Inch

CPI – Common Programming Interface

CPL – Combined Programming Language

CPM – Control Program for Microcomputers (sometimes CP/M)

CPM – Control Program Monitor (sometimes CP/M)

CPO – Chief Petty Officer

CPO – Chief Post Office

CPR – Canadian Pacific Railway

CPS – Characters Per Second

CPSR – Computer Professionals for Social Responsibility

CPT – CaPTain

CPU – Central Processing Unit

CPW – Certified Public Weigher

CQ – Change of Quarters

CR – Carriage Return (ASCII 15 octal)

CRA – Cambridge Redevelopment Authority

CRAF – Comet Rendezvous / Asteroid Flyby [Space]

CRAM – Card Random Access Memory (NCR, but maybe others)

CRC – Chemical Rubber Company

CRC – Cyclic Redundancy Check

CREG – Concentrated Range Extension with Gain

CREN – The Corporation for Research and Educational Networking (merge of BITNET and CSNet)

CRRES – Combined Release / Radiation Effects Satellite [Space]

CRRES – Combined Release and Radiation Effects Satellite [NASA]

CRT – Cathode Ray Tube (also generic reference to a terminal)

CRTC – Canadian Radio-television and Telecommunications Commission

C&S – Chivalry & Sorcery

CS – Civil Servant

CS – Computer Science; Computing Science

CS – County Seat

CSA – Confederate States of America

CSAB – Computing Sciences Accreditation Board

CSACS – Centralized Status, Alarm and Control System

CSC – Computer Sciences Corporation

CSDC – Circuit Switched Digital Capability

CSF – Critical Success Factor

CSI – Commercial Systems Integration

CSIS – Canadian Security and Intelligence Service

CSL – Coin Supervising Link

CSM – Command and Service Module (Apollo spacecraft) [Space]

CSM – Command Sergeant Major

CSMA – Carrier Sense Multiple Access

CSMA/CA Carrier Sense Multiple Access with Collision Avoidance

CSMA/CD Carrier Sense Multiple Access with Collision Detection

CSNET – Computer + Science Network (merged with BITNET to make CREN)

CSO – Central Services Organization

CSOC – Consolidated Space Operations Center (at Colorado Springs)

CSP – Control Switching Point

CSR – Control and Status Register

CSR – Customer Service Representative [Telephony]

CSRG – Computer Systems Research Group

CSRS – civil Service Retirement System

CSS – Customer Switching System

CST – Central Standard Time

CSU – Channel Service Unit

CT – Central Time

C&T – Communications & Tracking [Space]

CT – Connecticut

CTC – Canadian Transport Commission

CTC – Centralized Traffic Control [Railroading]

CTD – Computing and Telecommunications Division

CTIO – Cerro Tololo Inter-american Observatory

CTIO – Cerro Tololo Interamerican Observatory [Space]

CTNE – Compania Telefonica Nacional de Espana

CTS – Clear To Send (EIA RS-232-C)

CTS – Compatible Timesharing System

CTV – Canadian TeleVision network

CU – Close-Up

CUA – Common User Access

CUL – See You Later [Net jargon]

CV – Curriculum Vitae

CW – Car Wars

CW – Chemical Warfare

CW – Child Welfare

CW – Churchwarden

CW – Churdwarden

CW – Continuous Wave

CWO – Cash With Order

CWO – Chief Warrant Officer

CWRU – Case Western Reserve University

CXI – Common X-windows Interface

CY – Calendar Year

CYO – Catholic Youth Organization

CZ – Canal Zone

D – Depth

DA – Days after Acceptance

DA – Department of Agriculture

DA – Deposit Account

D/A – Digital to Analog converter

DA – Directory Assistance (/C = computerized, /M = Microfilm) [Telephony]

DA – District Attorney

DA – Don’t Answer [Telephony] (may be more general)

DAC – Digital to Analog Converter

DA/C – Directory Assistance/Computerized

DACCS – Digital Access Cross Connect System [Telephony] (suspect, see DACS)

DACS – Digital Access Cross-connect System [Telephony]

DAD – Draft ADdendum

DAG – Directed Acyclic Graph

DAL – Dedicated Access Line [Telephony]

DA/M – Directory Assistance/Microfilm

DAP – Division Advisory Panel (of NSF (q.v.) DNCRI (q.v.))

DAR – Daughters of the American Revolution

DARE – Drug Abuse Resistance Education

DARPA – Defense Advanced Research Projects Agency (of the DoD, see also ARPA)

DASD – Direct Access Storage Device

DAT – Digital Audio Tape

DATA – Defense Air Transport Administration

DAV – Disabled American Veterans

DB – DataBase

db – decibel(s)

dba – doing business as

DBF – DBase Format

DBME – DataBase Managment Environment

dbms – DataBase Management System (rdbms for Relational …)

DBRAD – Data Base Relational Application Directory

DC – Direct Current (dc, see also AC)

DC – District of Columbia

DCA – Defense Communications Agency

DCA – Distributed Communication Architecture

DCA – Document Content Architecture

DCC – Descriptive Cataloging Committee

DCCO – Defense Commercial Communications Office

DCD – Data Carrier Detect (sometimes CD (q.v.)) (EIA RS-232-C)

DCE – Data Communication Equipment

DCL – Digital Command Language

DCP – Distributed Communications Processor

DCTS – Dimension Custom Telephone Service

DD – Daredevils

DD – Data Dictionary

DD – Days after Date

DD – Demand Draft

DD – Dishonorable Discharge

DD – Disk Drive

DD – Doctor of Divinity

D&D – Dungeons & Dragons

DDC – Digital Data Converter

DDCU – DC-to-DC Converter Unit [Space]

DDD – Direct Distance Dialing [Telephony] (principally US, elsewhere STD)

DDL – Document Description Language

DDN – Defense Data Network

DDP – Distributed Data Processing

DDS – Dataphone Digital Service [AT&T]

DDS – Digital Data Service

DDS – Direct Digital Service

DDS – Doctor of Dental Science

DDS – Doctor of Dental Surgery

DDT – DEC Debugging Tape

DDT – Di-<something> (pesticide)

DDT – Dynamic Debugging Technique

DE – Delaware

DEA – Drug Enforcement Agency [US Government]

DEAR – Department of Energy Acquisition Regulation

DEC – Digital Equipment Corporation [Corporate name]

DECUS – Digital Equipment Corporation Users Society

DES – Data Encryption Standard [NIST]

DEW – Distant Early Warning (as in DEW Line)

DF – Damage Free

D/F – Direction Finding

DFC – Distinguished Flying Cross

DFD – Data Flow Diagram

DFE – Data Flow Editor

DFM – Distinguished Flying Medal

DFN – Deutsche Forschungsnetz Verein (German Research Network Association)

DFRF – Dryden Flight Research Facility [Space]

DFS – Depth-First Search

DFW – Dallas-Ft.Worth (regional airport)

DG – Data General [Corporate name]

DG – Dei Gratia (by the grace of God)

DG – Director General

DGSC – Defense General Supply Center

DHHS – Department of Health and Human Services

DHSS – british Department of Health and Social Security

DHSS – Department of Health and Social Security (British)

DIA – Document Interchange Architecture

DIAD – (magnetic) Drum Information Assembler / Dispatcher

DIAL – Direct Information Access Line

DIAS – Defense Automatic Integrated System

DID – Direct Inward Dialing [Telephony]

DIF – Document Interchange Format

DIN – Deutsches Institut fur Normung

DIRE – Dire Is Really Emacs

DIS – Draft International Standard [ISO]

DISA – Data Interchange Standards Association

DISOSS – Distributed Office Support System [IBM]

DIY – Do It Yourself

DJ – Disc Jockey

DLA – Defense Logistics Agency

DLI – Data Link Interface(?)

DLL – Data Link Layer [ISO OSI]

DLL – Dial Long Line equipment

DLO – Dead Letter Office

DM – Dungeon Master

DMA – Direct Memory Access

DMD – Doctor of Dental Medicine

DME – Distance Measuring Equipment

DMF – Probably part of an X.400 address in Europe

DMOS – Diffusion Metal Oxide Semiconductor (see MOS)

DMSP – Defense Meteorological Satellite Program [Space]

DMV – Department of Motor Vehicles

DMV – Department of Motor Vehicles (Calif)

DMZ – DeMilitarized Zone

DNA – DeoxyriboNucleic Acid

DNA – Digital Network Architecture [DEC]

DNCRI – [NSF] (q.v.) Division of Networking and Communications Research and Infrastructure

DNHR – Dynamic NonHierarchical Routing

DNIC – Data Network Identification Code [Telephony]

DNIS – Dialed Number Identification Service (see also DID) [Telephony]

DNL – Director of Naval Laboratories

DNR – Dialed Number Recorder [Telephony]

DNS – Domain Name System

DOA – Dead On Arrival

DOB – Date Of Birth

DOC – Dynamic Overload Control

DOD – Department Of Defense [US Government] (sometimes DoD)

DOE – Department of Energy [US Government]

DOHC – Dual OverHead Cams [Automotive]

DOMAIN – Distributed Operating Multi Access Interactive Network (Apollo)

DOS – Disk Operating System

DOT – Department Of Transportation [US Government]

DOT&E – Director, Operational Test and Evaluation

DOV – Data Over Voice [Telephony]

DOY – Day of Year

DP – Data Processing

DP – Dial Pulse [Telephony]

DP – Displaced Persons (expelled from native land)

DP – Display Postscript

DP – Double Penetration

DP – Double Play

DP – Draft Proposal

DPA – Delegation of Procurement Authority

DPANS – Draft Proposed American National Standard

DPI – Dots Per Inch

DPS – Display PostScript

DQ – Dairy Queen

DQ – Dragon Quest

DQDB – Distributed Queue Dual Bus (IEEE 802.6) [Telephony, Networking]

DQL – Database Query Language

DR – Dead Reckoning

DR – Dining Room

DRAM – Dynamic Random Access Memory (as opposed to static RAM)

DRD – Data Reading Device

DRE – Directional Reservation Equipment

DRG – Democratic Republic of Germany (East Germany)

DRI – Defense Research Internet

DRI – Digital Research, Incorporated [Corporate name]

d.s. – died single [Genealogy]

DS – Double-Sided

DS – Draft Standard

DSA – Dial System Assistance

DSE – Data Structure Editor

DSEE – Domain Software Engineering Environment

DSM – Distinguished Service Medal

DSO – Distinguished Service Order

DSP – Decessit Sine Prole (died without issue)

DSP – Digital Signal Processing

DSRI – Digital Standard Relational Interface

DSS – Decision Support System

DSS – Direct Station Selection [Telephony]

DST – Daylight Saving Time

DSTN – Double SuperTwisted Nematic

DSU – Digital Service Unit

DT – Delirium Tremens

DTE – Data Terminal Equipment

DTF – Dial Tone First payphone [Telephony]

DTMF – Dial Tone Multi Frequency [Telephony]

DTP – DeskTop Publishing

DTR – Data Terminal Ready (EIA RS-232-C)

DUI – Driving Under the Influence

DUT – Device Under Test

DV – Deo Vo lente (God willing)

DVM – Digital Volt Meter

DVM – Doctor of Veterinary Medicine

DWAPS – Defense Warehousing Automated Processing System

DWI – Died Without Issue [Genealogy]

DWI – Driving While Intoxicated

DWIM – Do What I Mean

DX – Distance (as in long distance radio communication)

DXT – Data eXtractT facility

d.y. – died young [Genealogy]

E – East

E – Espionage

EADASS – Engineering and Administrative Data AcquiSition System

EAFB – Edwards Air Force Base [Space]

EAN – Certainly part of an X.400 Address in Europe

EARN – European Academic Research Network

EAS – Extended Area Service (or Engineering Admin. System)

EASI – European Academic Supercomputer Initiative (of IBM)

EBCDIC – Extended Binary Coded Decimal Interchange Code

EC – Exchange Carrier [Telephony]

ECAFE – Economic Commission for Africa and the Far East

ECASS – Electronically Controlled Automatic Switching System

ECASS – Export Control Automated Support System

ECC – Error Correction Code

ECC – Error Correction Code (corrects error in memory or transmission)

ECCM – Electronic Counter-CounterMeasures

ECDO – Electronic Community Dial Office

ECG – ElectroCardioGram

ECL – Emitter Coupled Logic (see also TTL)

ECLSS – Environmental Control and Life Support System [Space]

ECM – Electronic Counter Measure

ECM – European Common Market

ECMA – European Computer Manufacturers Association

ECO – Ecological

ECO – Electronic Central Office

ECO – Engineering Change Order

ECPA – Electronic Communications Privacy Act [US law]

ECS – Environmental Control System [Space]

ECT – ElectroConvulsive Therapy

ECV – Electric Cargo Vehicle [NASA OEXP]

ED&D – Expert Dungeons & Dragons

EDGAR – Electronic Data Gathering, Analysis, and Retrieval

EDI – Electronic Data Interchange

EDIF – Electronic Design Interchange Format

EDO – Extended Duration Orbiter [Space]

EDP – Electronic Data Processing

EDS – Electronic Data Systems

EDT – Eastern Daylight Time

EDTA – Ethylene Diamine Tetraacetic Acid

EDTCC – Electronic Data Transmission Communications Central

EE – Electrical Engineer

EE – Electrical or Electronics Engineer

EEC – European Economic Community

EEC – European Economic Comunity

EEG – ElectroEncephaloGram

EEL – Epsilon Extension Language

E&EO – Errors and Omissions Excepted

EEPROM – Electrically Erasable Programmable Read Only Memory

EFF – Electronic Frontier Foundation

e.g. – ??? (Latin(?): for example)

EGA – Enhanced Graphics Adapter

EGP – Exterior Gateway Protocol [Internet]

EGRET – Energetic Gamma Ray Experiment Telescope (on GRO) [Space]

EHF – Extremely High Frequency (30-300GHz)

EIA – Electronic Industries Association

EINE – EINE Is Not Emacs

EISA – Extended Industry-Standard Architecture

EISS – European Intelligence Support System

EKG – ElectroKardioGramm (see ECG)

EL – ElectroLuminescent (as in display)

ELF – Extremely Low Frequency

ELO – Electric Light Orchestra

ELP – Emerson, Lake and Palmer (or Powell)

ELV – Expendable Launch Vehicle [Space]

E&M – “Ear and Mouth”; receive and transmit leads of a signalling system

EM – Enlisted Man (see EW)

EMA – Electronic Mail Association

EMACS – Editor MACroS

EMACS – Eight Megabytes And Constantly Swapping

E-MAIL – Electronic MAIL

EMF – ElectroMotive Force

EMF – ElectroMotive Force (voltage)

EMI – ElectroMagnetic Interference

EMP – Electromagnetic Pulse

EMPRESS EnvironMental Pulse Radiation Environment Simulator for Ships

EMR – ElectroMagetic Response

EMR – ElectroMagnetic Response

EMS – Electronic Message System

EMS – Extended Memory Specification

EMT – Emergency Medical Technician

EMU – ElectroMagnetic Unit

EMU – Extravehicular Mobility Unit [Space]

ENIAC – Electronic Numerical Integrator and Calculator

ENS – ENSign

EO – End Office [Telephony]

EO – Erasable Optical

EOF – End Of File

EOM – End Of Month

EOS – Earth Observing System [Space]

EOWG – Engineering and Operations Working Group (under FNC)

EP – Experience Points

EP – Extended Play

EPA – Environmental Protection Agency

EPOS – Engineering and Project-management Oriented Support system

EPRI – Electric Power Research Institute

EPROM – Erasable Programmable Read Only Memory

EPS – Encapsulated PostScript

EPT – Empire of the Petal Throne

EQ – Educational Quotient (see IQ)

ER – Emergency Room

ERA – Earned Run Average

ERA – Entity-Relationship-Attribute

ERA – Equal Rights Amendment

ERD – Entity-Relation Diagram

ERE – Entity Relationship Editor

ERT – Earth Resources Technology [Space]

ES – Expert System

ESA – European Space Agency

ESA – European Space Agency [Space]

ESAC – Electronic Systems Assistance Center

ESDI – Enhanced Standard Device Interface

ESE – East South East

ESF – Extended Superframe Format [Telephony]

ESM – Electronic Support Measures

ESnet – Energy Sciences network (DoE) [Networking]

ESO – European Southern Observatory

ESO – European Southern Observatory [Space]

ESP – Extra Sensory Perception

ESPS – Entropic Signal Processing System

ESS – Electronic Switching System [Telephony]

ESSEX – Experimental Solid State EXchange

EST – Eastern Standard Time

ET – Eastern Time

ET – Extra Terrestrial [Space]

ET – (Shuttle) External Tank [Space]

ETA – Estimated Time of Arrival

ET/ACC – External Tank/Aft Cargo Carrier (see also ET) [Space]

ETC – Et cetera, and so on…

ETD – Estimated Time of Departure

ETFD – Electronic Toll Fraud Device [Telephony]

ETH – Eidgn:oessiche Technische Hochschule (Swiss Federal Institute of Technology)

ETLA – Extended Three Letter Acronym [Space]

ETO – Earth-to-Orbit [Space]

ETR – Eastern Test Range [Space]

ETS – Electronic Translator System

ETV – Education TeleVision

EUUG – European Unix User Group

EUV – Extreme UltraViolet

EUV – Extreme UltraViolet [Space]

EUVE – Extreme UltraViolet Explorer [Space]

EVA – ExtraVehicular Activity

EVA – ExtraVehicular Activity [Space]

EVX – Electronic Voice eXchange

EW – Electronic Warfare

EW – Enlisted Woman (see EM)

EWOS – European Workshop for Open Systems

FA – Football Association (British soccer–a word derived from Association)

FAA – Federal Aviation Agency [US Government]

FACD – Foreign Area Customer Dialing

FAO – Food and Agriculture Organization [US Government]

FAQ – Frequently Asked Questions [Space]

FAR – Federal Acquisition Regulations

FAS – Foreign Agricultural Service

FAS – Free Alongside Ship

FASST – Flexible Architecture Standard System Technology

FAST – Fast Auroral SnapshoT explorer [Space]

FAT – Foreign Area Translation

FAX – FAcsimile

FB – Freight Bill

FBI – Federal Bureau of Investigation [US Government]

FCC – Federal Communications Commission [US Government]

FCC – Federal Computer Conference

FCCSET – Federal Coordinating Committee for Science, Education and Technology (under OSTP) {Maybe Eng. for Edu.??}

FCO – Field Change Order

FCO – Frequency Controlled Oscillator

FCS – Frame Check Sequence

FDA – Food and Drug Administration [US Government]

FDDI – Fiber Digital Data Interface

FDDI – Fiber Distributed Data Interface

FDHD – Floppy Drive High Density

FDIC – Federal Deposit Insurance Corporation

FDIC – Federal Deposit Insurance Corporation [US Government]

FDM – Frequency Division Multiplexing

FDR – Franklin Delano Roosevelt [US President]

FE – Field Engineer (see also CE, SE)

FEA – Finite Element Analysis

FEDSIM – FEDeral Systems Integration and Management center

FEMA – Federal Emergency Management Agency

FEMF – Foreign EMF (q.v.) (a.k.a. Cross Battery) [Telephony]

FEPC – Fair Employment Practices Commission

FEPG – Federal Engineering Planning Group (of FNC under EOWG, originally of FRICC)

FERS – Federal Employees Retirement System

FET – Federal Excise Tax

FET – Field Effect Transistor

FFA – Future Farmers of America

FFT – Fast Fourier Transform

FFT – Fast Fourier Transform [Space]

FG-A – Feature Group A [Telephony] (Line Side termination for LD carriers)

FG-B – Feature Group B [Telephony] (Trunk Side termination for LD carriers (aka ENFIA B), 950 service)

FG-D – Feature Group D [Telephony] (Trunk Side termination for LD carriers, 1+ service)

FGS – Fine Guidance Sensors (on HST) [Space]

FHA – Federal Home Administration

FHA – Future Homemakers of America

FIB – Focused Ion Beam

FICA – Federal Insurance Contributions Act

FIDO – Fog Investigation Dispersal Operation

FIFO – First In First Out (as in registers and buffers)

FILO – First In Last Out (see also FIFO)

FIMS – Forms Interface Management System

FINE – FINE Is Not Emacs

FIO – Frequency In and Out

FIPS – Federal Information Processing Standard

FIR – Far InfraRed [Space]

FIR – Finite Impulse Response

FIRMR – Federal Information Resource Management Regulation

FIT – Federal Information Technologies, inc.

FITS – Flexible Image Transport System [Space]

FIX – Federal Inter-agency eXchange [Networking]

FL – Florida

FLACC – Full Level Algol Checkout Compiler

FLEA – Four Letter Extended Acronym

FLL – Fixed Loss Loop [Telephony]

FLOP – FLoating point OPeration

FLOPS – FLoating-point OPerations per Second

FLRA – Federal Labor Relations Authority

FM – Frequency Modulation

FMB – Federal Maritime Board

FMCS – Federal Mediation and Conciliation Service

FMR – Follow Me Roaming [Telephony]

FMS – Financial Management Service (Treasury Dept) [US Government]

FMS – Forms Management System

FNC – Federal Networking Council (formerly FRICC) [US Government] (under OSTP)

FO – Foreign Office

FO – Forward Observer

FOAC – Federal Office Automation Center

FOB – Free On Board

FOB – Full Of Bull (aperiodical of) [TMRC]

FOC – Faint Object Camera (on HST) [Space]

FOC – Free Of Charge

FOIA – Freedom Of Information Act

FOIMS – Field Office Information Management System

FOIRL – Fiber Optic Inter(?) Repeater(?) Link(?) [Ethernet]

FOOBAR – See FUBAR [Net jargon]

FOR – Free On Rail

FORCS – Faa’s Operational Reporting Communication System

FORD – Fix Or Repair Daily [Humor]

FORD – Found On Road Dead [Humor]

FORTRAN FORmula TRANslator

FOS – Faint Object Spectrograph (on HST) [Space]

FOSE – Federal Office Systems Exposition

FOT – Fiber Optic Transceiver [Ethernet]

FOT – Free On Truck

FOV – Field Of View

FPA – Floating Point Accelerator

FPC – Fish Protein Concentrate

FPE – Floating Point Engine

FPHA – Federal Public Housing Authority

FPLA – Field Programmable Logic Array (see PLA)

FPM – Feet Per Minute

FPO – Field Post Office

FPO – Fleet Post Office

fps – Feet Per Second

FPU – Floating Point Unit

FQDN – Fully Qualified Domain Name [TCP/IP] (DNS)

FR – Frame Relay [Telephony, Networking]

FRACTAL FRACTional dimensionAL

FRED – Fred Resembles Emacs Deliberately

FRG – Federal Republic of Germany (West Germany)

FRICC – Federal Research Internet Coordinating Committee (now FNC, q.v.) [Networking, US Government]

FROG – Free Rocket Over Ground

FRPG – Fantasy Role Playing Game

FRS – Federal Reserve System

FS – Field Service

FS – File System

FS – Full Standard

FSF – Free Software Foundation

FSK – Frequency Shift Keying

FSLIC – Federal Savings and Loan Insurance Corporation

FSS – Federal Supply Service

FSW – Forward Swept Wings

Ft – Foot

FTAM – File Transfer And Management (ISO upscale FTP)

FTC – Federal Trade Commission

FTL – Faster Than Light

FTP – File Transfer Protocol (esp. of the TCP/IP suite)

FTS – Federal Telecommunications System [Telephony, US Government]

FTS – Flight Telerobotic Servicer [Space]

FUBAR – F***ed Up Beyond All Recognition/Repair

FUBAR – Fouled Up Beyond All Recognition/Repair

FUSE – Far Ultraviolet Spectroscopic Explorer [Space]

FW – Fringeworthy

FWD – Front Wheel Drive

FWHM – Full Width at Half Maximum [Space]

FX – Foriegn eXchange [Telephony]

FY – Fiscal Year

FYI – For Your Information

G – General audiences [Movie rating]

G – Gravity

GA – Gamblers Anonymous

GA – General Assembly

GA – General Average

GA – General of the Army

GA – Georgia

GAAP – Generally Accepted Accounting Principles

GAB – Group Audio Bridging [Telephony]

Gaia – Earth’s self-sustaining Biosphere (Not an acronym, from some ancient language, I think)

GAN – Global Area Network

GAO – General Accounting Office [US Government]

GAR – Grand Army of the Republic

GARR – Gruppo Arminizzazione Rete por la Ricerca (Italian Research Network Harmonization Group)

GAS – Get-Away Special [Space]

GATT – General Agreement on Tariffs and Trade

GAW – Guaranteed Annual Wage

GAW – Guarenteed Annual Wage

GB – Gangbusters

GB – GigaByte

GB – Great Britain

GBIP – General Purpose Interface Bus

GBT – Green Bank Telescope [Space]

GC – Garbage Collection (LISP)

GC – Gas Chromatograph (or Chromatography)

GCA – Ground Controlled Approach

GCC – Gnu C Compiler

GCD – Ground Controlled Descent

GCL – Graphics Command Language

GCM – General Court Martial

GCR – Group-Coded Recording (magnetic tape, 6250 bpi)

GCT – Greenwich Civil Time

GCVS – General Catalog of Variable Stars [Space]

GDB – Gnu DeBugger

GDP – Gross Domestic Product

GDS – Great Dark Spot [Space]

GE – General Electric

GEM – Giotto Extended Mission [Space]

GEM – Graphics Environment Manager

GEO – Geosynchronous Earth Orbit [Space]

GHQ – General HeadQuarters

GHRS – Goddard High Resolution Spectrograph (on HST) [Space]

GHz – Giga HertZ (unit of frequency, 1,000,000,000 cycles per second)

GI – Galvanized Iron

GI – Gastro Intestinal (as in upper GI)

GI – General Issue

GI – Government Issue

GID – Group ID [UNIX]

GIF – Graphics Interchange Format

GIGO – Garbage In Garbage Out

GIN – Graphics INput

GISS – Goddard Institute for Space Studies

GKS – Graphical Kernel Standard

GKS – Graphics Kernel System

GM – Game Master

GM – General Manager

GM – General Motors [Corporate name, Automobile]

GM – Guided Missile

GMBH – Gesellschaft Mit Beschraenkter Haftung

GMC – Giant Molecular Cloud [Space]

GMD – Gesellschaft f:ur Mathematik und Datenverarbeitung (German Institute for Mathematics and Data Processing)

GMRT – Giant Meter-wave Radio Telescope [Space]

GMT – Greenwich Mean Time (also called UT)

GNP – Gross National Product

GNU – GNU’s Not Unix

GOES – Geostationary Orbiting Environmental Satellite [Space]

GOES – Geostationary Orbiting Environmental Satellites [Space]

GOSIP – Government Open Systems Interconnection Profile (calls for government procurement of ISO/CCITT products)

GOSIP – Government OSI Profile

GP – General Practitioner

GP – General Purpose (RR engines and origin of Jeep) [Railroading, Automobile]

GPC – General Purpose Computer [Space]

GPI – Graphics Programming Interface

GPIB – General Purpose Interface Bus

GPIB – General-Purpose Interface Bus

GPL – GNU General Public Licence

GPO – General Post Office

GPO – Government Printing Office

GPS – Global Positioning System

GPS – Global Positioning System [Space]

GQ – General Quarters

GRB – Gamma Ray Burst(er)

GREP – Global Regular Expression Print, g/re/p, (UNIX command)

GREP – Global Regular Expression Print [UNIX]

GRO – Gamma Ray Observatory [Space]

GRS – Gamma Ray Spectrometer (on Mars Observer) [Space]

GRS – Great Red Spot [Space]

GS – General Schedule

GS – Glide Slope

GSA – General Services Administration

GSA – General Services Adminstration [US Government]

GSA – Girl Scouts of America

GSBCA – General Services administration Board of Contract Appeals

GSC – Guide Star Catalog (for HST) [Space]

GSFC – Goddard Space Flight Center (Greenbelt, MD) [NASA, Space]

GSI – Gesellschaft f:ur Schwerionenforschung (German Federal Research Institute for Heavy Ion Research)

GSM – Global System Mobile

GSM – Groupe Speciale Mobile (Committee Designing preceding)

GSTS – Ground-based Surveillance and Tracking System

GT – Gross Ton

GTE – General Telephone and Electric [Corporate name]

GTO – Geostationary Transfer Orbit [Space]

GTSI – Government Technology Services, inc.

GUI – Graphical User Interface

GW – Gamma World

GWEN – Ground Wave Emergency Network

GWM – Generic Window Manager [X]

H – Harn

H – Height

HACD – Home Area Customer Dialing

HAL – Heuristically programmed ALgorithmic computer (movie 2001)

HAM – Hold And Modify

HAO – High Altitude Observatory [Space]

Hb – HemogloBin

HBM – Her British Majesty; His British Majesty

HBO – Home Box Office

HC – Holy Communion

HC – House of Commons

HCFA – Health Care Financing Administration

HCFC – hydrochlorofluorocarbon [Chemical]

HCL – High Cost of Living

HD – Hard Disk

HD – Heavy Duty

HD – Henry Draper catalog entry [Space]

HDA – Head Disk Assembly (in winchester disk drives)

HDBV – Host Data Base View

HDL – High Density Lipoprotein

HDLC – High-level Data Link Control [Networking]

HDTV – High Definition Television

HE – His Eminence

HE – His Excellency

HEAO – High Energy Astronomical Observatory [Space]

HEDM – High Energy-Density Matter [Space]

HEMP – Help End Marijuana Prohibition

HEO – High Earth Orbit [Space]

HEPnet – High Energy Physics network [Networking]

HERO – Hazards of Electromagnetic Radiation to Ordnance

HF – High Fantasy

HF – High Frequency (3-30MHz)

HFE – Human Factors Engineering

HFS – Hierarchical File System

HGA – High Gain Antenna [Space]

HHS – (US Department of) Health and Human Services

HI – Hawaii

HIIPS – Hud Integrated Information Processing Services

HLC – Heavy Lift Capability [Space]

HLL – High-Level Language

HLV – Heavy Lift Vehicle [Space]

HMC – Halley Multicolor Camera (on Giotto) [Space]

HMOS – High performance Metal Oxide Semiconductor (see MOS)

HMS – His/Her Majesty’s Ship

HMT – His/Her Majesty’s Transport

HNPA – Home Numbering Plan Area [Telephony]

HOBIS – HOtel Billing Information System

HOL – High-Order System

HOTOL – HOrizontal Take-Off and Landing

HP – Hewlett Packard, Inc. [Corporate name]

HP – High Pressure

HP – Higher Power (sort of an AA “in” term, usually God)

HP – Hit Points

HP – HorsePower

HPGe – High Purity Germanium

HPL/T – High-Productivity Languages/Tools

HQ – HeadQuarters

HR – Hertzsprung-Russell (diagram) [Space]

HR – House of Representatives

HRH – Her Royal Highness

HRH – His Royal Highness

HRI – High Resolution Imager (on ROSAT) [Space]

HS – High School

HSB – Hue, Saturation, Brightness

HSP – High Speed Photometer (on HST) [Space]

HST – Hawaiian Standard Time

HST – Hubble Space Telescope [Space]

HT – High Tension (as in electric power transmission)

HTK – Hits To Kill

HUAC – House Unamerican Activities Committee

HUD – Heads Up Display

HUD – Housing and Urban Development [US Government]

HUPD – Harvard University Police Department

HUT – Hopkins Ultraviolet Telescope (ASTRO package) [Space]

HV – High Voltage

HVAC – Heating, Ventilation, and Air Conditioning

HW2000 – Highway 2000

HWM – High-Water Mark

Hz – HertZ (unit of frequency, cycles per second)

IAB – Internet Activities Board [Networking]

IAEA – International Atomic Energy Agency

IANA – Internet Assigned Numbers Authority (IANA@ISI.EDU)

IATA – International Air Transport Association

IAU – International Astronomical Union [Space]

IAUC – IAU Circular [Space]

IBM – Ingrained Batch Mentality

IBM – International Business Machines, Inc. [Corporate name]

IBM – Itty Bitty Machines

IBT – Illinois Bell Telephone

IC – Integrated Circuit

IC – Interexchange Carrier [Telephony] (see also IEC, IXC)

ICB – Interstate Computer Bank

ICBM – InterContinental Ballistic Missile

ICE – In-Circuit Emulator

ICE – International Cometary Explorer [Space]

ICI – Imperial Chemical Industries

ICJ – International Court of Justice

ICL – International Computers Ltd.

ICMP – Internet Control Message Protocol

ICP – Integrated Channel Processor

ICP – Inventory Control Points

ICRC – International Cosmic Ray Conference

ID – Idaho

ID – IDentification

IDA – Intercommunication Data Areas

IDA – International Dark-sky Association [Space]

IDA – International Development Association

IDDD – International Direct Distance Dial [Telephony]

IDE – Interactive Development Environments, inc

IDF – Intermediate Distributing Frame [Telephony]

IDL – Interactive Data Language [Space]

IDV – Interlibrational Derived Vehicle [Space]

i.e. – ???? (Latin(?): in other words (?))

IE – Indo-European

IEC – Inter-Exchange Carrier [Telephony] (see also IC, IXC)

IEE – Institute of Electrical Engineers [UK]

IEEE – Institute of Electrical and Electronic Engineers

IETF – Internet Engineering Task Force

IF – Intermediate Frequency (as in IF stage)

IFB – Invitation For Bids

IFC – International Finance Corporation

IFC – International Freighting Corporation

IFF – Identification – Friend or Foe

IFF – Interchange File Format

IFLA – International Federation of Library Associations

IFR – Instrument Flight Rules [Aviation]

IGES – Initial Graphics Exchange Standard

IGM – InterGalactic Medium [Space]

IGY – International Geophysical Year

IGY – International Geophysical Year [Space]

IHP – Indicated HorsePower

IHS – Integrated Hospital Support

IIA – Information Industry Association

IIE – Institute of Industrial Engineers

IIHF – International Ice Hockey Federation

IIL – Integrated Injection Logic

ILO – International Labor Organization

ILS – Instrument Landing System

ILV – Industrial Launch Vehicle [Space]

IMF – International Monetary Fund

IMHO – In My Humble Opinion [Net jargon]

IMO – In My Opinion [Net jargon]

IMP – Interface Message Processor [ARPANET/MILNET] (replaced by PSN)

IMSL – International Mathematical Subroutine Library

IN – Indiana

INADS – INitialization and ADministration System [Telephony]

INRA – Iesus Nazerenus Rex Iudaeorum (Jesus of Nazareth, King of the Jews)

INRIA – Institut National de Recherche en Informatique et Automatique

INS – Immigration and Naturalization Service

INTAP – INteroperability Technology Association for information Processing

INWATS – INward Wide Area Telephone Service [Telephony]

I/O – Input/Output

IO – Input/Output (sometimes I/O)

IOC – International Operating Center [Telephony, US]

IOD – Identified Outward Dialing

IOOF – International Order of Odd Fellows

IOTA – Infrared-Optical Telescope Array [Space]

IOTA – International Occultation Timing Association [Space]

IOU – I Owe you(U)

IP – Information Provider [Telephony]

IP – Innings Pitched

IP – Intermediate Point

IP – Internet Protocol

IPC – Inter-Process Communication

IPE – Integrated Programming Environment

IPMS – InterPersonal Message Services

IPS – Inertial Pointing System [Space]

IPS – Information Processing Standards

IPSE – Integrated Project-Support Environment

IQ – Intelligence Quotient (see EQ)

IR – Index Register

IR – Infra-Red

IRA – Individual Retirement Account

IRA – Irish Republican Army

IRAF – Image Reduction and Analysis Facility [Space]

IRAS – InfraRed Astronomical Satellite [Space]

IRBM – Intermediate Range Ballistic Missile

IRDS – Information Resource Dictionary Standard

IRDS – InfraRed Detection Set

IRE – Institute of Radio Engineers (old name for the now IEEE, which see)

IRM – Information Resources Management

IRMS – Information Resources Management Service

IRS – Internal Revenue Service

IRTF – Internet Research Task Force

IS – Information Systems

IS – International Standard [ISO] (Beyond the DIS Stage)

ISA – Industry-Standard Architecture

ISAM – Indexed Sequential Access Method

ISAS – Institute of Space and Astronautical Science (Japan) [Space]

ISBD – International Bibliographic Description

ISC – Information Services Center

ISC – International Switching Center

ISCH – Interstitial-Cell-Stimulating Hormone (same as LH)

ISDN – Integrated Services Digital Network [Telephony]

ISDT – Integrated Systems Development Tool

ISEE – International Sun Earth Explorer (usually ISEE-3)

ISF – Information Systems Factory

ISFUG – Integrated Software Federal User Group

ISI – Information Sciences Institute

ISM – InterStellar Medium [Space]

ISO – Infrared Space Observatory [Space]

ISO – International Organization for Standardization

ISO – International Standards Organization [Space]

ISODE – ISO Development Environment

ISOO – Information Security Oversight Office

ISPM – International Solar Polar Mission

ISPM – International Solar Polar Mission (now Ulysses) [Space]

ISR – Institute of Snow Research

ISRG – Independent Space Research Group

ISV – Independent Software Vendor

ISY – International Space Year [Space]

IT – Industrial Technology

IT – Information Technology

ITC – Inter-Task Communication

ITS – Incompatible Timesharing System

ITT – International Telephone and Telegraph

ITU – International Telecommunications Union

ITUSA – IT Users Standards Association

IUE – International Ultraviolet Explorer [Space]

IUS – Inertial Upper Stage

IUS – Inertial Upper Stage [Space]

IUV – Interlibrational Utility Vehicle [Space]

IXC – Inter-eXchange Carrier [Telephony] (see also IC, IEC)

IXI – International (pan-European) X.25 Infrastructure

JACM – Journal of the Association for Computing Machinery

JANET – Joint Academic Network (UK)

JBS – John Birch Society

JC – Jesus Christ

JC – Joint Compound (plumbing)

JC – Julius Caesar

JC – Junior College

JCA – Jewelry Crafts Association

JCAC – Joint Civil Affairs Committee

JCAE – Joint Committee on Atomic Energy

JCEE – Joint Council on Economic Education

JCET – Joint Council on Educational Television

JCS – Joint Chiefs of Staff

JD – Justice Department

JDS – John Dewey Society

JEM – Japanese Experiment Module (for SSF) [Space]

JES – John Ericsson Society

JET – Joint European Torus (fusion research)

JFK – John F. Kennedy

JFK – John F. Kennedy (international airport)

JFMIP – Joint Financial Management Improvement Program

JGR – Journal of Geophysical Research

JGR – Journal of Geophysical Research [Space]

JI – Justice, Inc.

JIC – Joint Intelligence Center

JIC – Just in Case

JILA – Joint Institute for Laboratory Astrophysics [Space]

JIM – Job Information Memorandum

JINTACCS – Joint INteroperability of TActical Command and Control Systems

JIS – Japan Industrial Standards

JISC – Japanese Industrial Standards Committee

JIT – Just In Time

JMS – John Milton Society

JNT – Joint Network Team (UK)

JO – Job Order

JO – Junior Officer

JOVE – Jonathan’s Own Version of Emacs

JOVIAL – Jules Own Version of the International Algorithmic Language

JPL – Jet Propulsion Laboratory

JPL – Jet Propulsion Laboratory [Space]

JRC – Junior Red Cross

JSC – Johnson Space Center

JSC – Johnson Space Center (NASA) [Space]

JSD – Jackson System Development

JSRC – Joint Services Review Committee

JTIDS – Joint Tactical Information Distribution Systems

JV – Junior Varsity

JvNC – John von Neumann (Super Computer) Center

JvNCnet John von Neumann (Super Computer) Center network

K – Kilo- (metric 1000)

K9 – canine (K9 corps – army dogs)

KAIST – Korean Advanced Institute of Science and Technology

KAO – Kuiper Airborne Observatory [Space]

KB – KiloByte

KC – King’s Counsel (QC when queen reigning)

KC – Knights of Columbus

KD – Kiln Dried

KD – Knocked Down

KDCI – Key Display Call Indicator

KERMIT – Kl-10 Error-free Reciprocal Micro Interconnect over Tty lines

KET – Kentucky Educational Television

KHz – Kilo HertZ (unit of frequency, 1000 cycles per second)

KI – Kiwanis International

KIA – Killed In Action

KIAS – Knot Indicated Air Speed

Km – Kilometers

KO – Knock Out [Boxing, Electric]

KP – Key Pulse [Telephony]

KP – Kitchen Police

KPNO – Kitt Peak National Observatory

KPO – KeyPunch Operator

KQC – King’s College London

K&R – Kernighan and Ritchie, the c programming language

KS – King’s Scholar

KSC – Kennedy Space Center (NASA) [Space]

KSU – Key System Unit [Telephony]

KTB – Cretaceous-Tertiary Boundary (from German) [Space]

KTS – Key Telephone System [Telephony]

KTU – Key Telephone Unit [Telephony]

KWIC – Key Word In Context

KY – Kentucky

L1 – Lagrange Point #1 35,000 Miles above moon [Space]

L2 – Lagrange Point #2 40,000 Miles behind moon [Space]

L3 – Lagrange Point #3 (?? 35,000 Miles below moon) [Space]

L4 – Lagrange Point #4 240,000 mile Earth orbit [Space]

L5 – Lagrange Point #5 240,000 mile Earth orbit [Space]

LA – Los Angeles

LA – Louisiana

LA – Low Altitude

LADAR – LAser Detection And Ranging

LAM – Master of Liberal Arts

LAMA – Local Automatic Message Accounting [Telephony]

LAN – Local Apparent Noon

LAN – Local Area Network

LANL – Los Alamos National Laboratory [Space]

LANL – Los Alamos (NM) National Laboratory

LAPB – Link Access Procedure (Balanced)

LAPD – Link Access Procedure (??)

LAPD – Los Angeles (CA, US) Police Department

LAR – Local Acquisition Radar

LaRC – Langley Research Center (NASA) [Space]

LASER – Light Amplification by Stimulated Emission of Radiation

LAT – Local Apparent Time

LATA – Local Access and Transport Area [Telephony]

LAX – Los Angeles International Airport

LB – Light Bomber

LB – pound (LiBra)

LBHS – Long Beach High School

LBL – Lawrence Berkeley (Calif.) Labs

LBS – Pounds

LC – inductor-Capacitor circuit (as in filters, L is symbol inductance)

LCD – Liquid Crystal Display

LCD – Lowest Common Denominator

LCDR – Lieutenant Commander

LCL – Less than Carload Lot [Railroading]

LCL – Lunar Cargo Lander [NASA OEXP]

LCM – Least Common Multiple

LCM – Life Cycle Management

LCS – Laboratory for Computer Science (of MIT)

LCT – Landing Craft Tanks

LD – Long Distance [Telephony]

LDC – Long Distance Carrier [Telephony]

LDEF – Long Duration Exposure Facility [Space, NASA]

LDF – Large Deployable Reflector [Space]

LDL – Low Density Lipoprotein

LDX – Long Distance eXtender [Telephony]

LEAP – Low-power Enhanced At Portable

LEC – Local Exchange Carrier [Telephony]

LED – Light Emitting Diode

LEM – Lunar Excursion Module (a.k.a. LM) (Apollo spacecraft) [Space]

LEO – Low Earth Orbit [Space]

LEP – Large Electron-Positron collider [CERN]

LeRC – Lewis Research Center (NASA) [Space]

LEST – Large Earth-based Solar Telescope [Space]

LF – Low Frequency (30-300KHz)

LFSA – List of Frequently Seen Acronyms (!) [Space]

LGA – Low Gain Antenna [Space]

LGM – Little Green Men [Space]

LH – Left Hand

LH – Liquid Hydrogen (also LH2 or LHX) [Space]

LH – Lower Half

LH – Luteinizing Hormone (same as ISCH)

LHC – Large Hadron Collider [CERN]

LHD – Litterarum Humaniorum Doctor (doctor of human letters)

LHS – Left Hand Side

LI – Long Island

LIFIA – Laboratoire d’Informatique Fondamentale et d’Intelligence Artificielle

LIFO – Last In First Out (see FIFO)

LINC – Laboratory INstrument Computer

LISA – Large Installation Systems Administration (USENIX specific?)

LISP – LISt Processing Language

LIU – Line Interface Unit

LL – Late Latin

LL – Long Lines [Telephony]

LLB – Legum Baccalaureus (bachelor of laws)

LLD – Legum doctor (doctor of laws)

LLN – Line Link Network [Telephony]

LLNL – Lawrence Livermore National Laboratories

LLO – Low Lunar Orbit [Space]

LLOX – Lunar Liquid Oxygen [Space]

LLP – Line Link Pulsing [Telephony]

LM – Life Master (Contract Bridge ranking)

LM – Lunar Module (a.k.a. LEM) (Apollo spacecraft) [Space]

LMC – Large Magellanic Cloud (see SMC)

LMC – Large Magellanic Cloud [Space]

LMOS – Line Maintenance Operations System [Telephony, AT&T]

LN2 – Liquid N2 (Nitrogen) [Space]

LNG – Liquified Natural Gas

LOA – Lands of Adventure

LOFT – Launch Operations Flight Test [Space]

LOOPS – Lisp Object Oriented Programming System

LOP – Lines Of Position

LOSF – Lunar Orbit Staging Facility [Space]

LOTS – Low Overhead Timesharing System

LOX – Liquid Oxygen

LOX – Liquid OXygen [Space]

LP – Long Play(ing) (record)

LP – Low Pressure

LPC – Linear Predictive Coding (speech processing)

LPDA – Link Problem Determination Aid

LPF – League for Programming Freedom

LPG – Liquefied Petroleum Gas

LPG – Low Pressure Gas

LPL – Lunar Personnel Lander [NASA OEXP]

LPN – Licensed Practical Nurse

LPP – Licensed Program Products

LPR – Line PrinteR

LPT – Lunar Propellant Tanker [NASA OEXP]

LPV – Lunar Piloted Vehicle [NASA OEXP]

LRB – Liquid Rocket Booster [Space]

LRBM – Long Range Ballistic Missile

LRC – Longitudinal Redundancy Character

LRU – Least Recently Used

LRU – Line Replaceable Unit

LRV – Light Rail Vehicle [Railroading]

LS – Left Side

LS – Letter Signed

LS – Locus Sigilli (place of seal)

LSAP – Logical(?, maybe Link) Service Access Point [OSI, Networking]

LSB – Least Significant Bit; Least Significant Byte

LSB – Lower Side Band

LSC – Lecture Series Committee (of MIT)

LSC – LightSpeed C

LSD – Least Significant Digit

LSD – LySergic acid Diethylamide

LSD – pounds (Libra), shillings (Sestertii), and (old) pence (Denarii)

LSI – Large Scale Integration

LSP – LightSpeed Pascal

LSR – Local Standard of Rest [Space]

LSS – Life Support System

LSS – Loop Switching System

LSSD – Level-Sensitive Scan Detection

LT – Long Ton

LT – Low Tension

LTC – Lieutenant Colonel

LTJG – Lieutenant Junior Grade

LTL – Less than Truckload Lot

LTP – Lunar Transient Phenomenon [Space]

LUG – Local Users Group

LUT – Look-Up Table

LWM – Low-Water Mark

LWT – London Weekend Television [Corporate name]

LZ – Landing Zone

M – Mega- (metric 10^6)

m – meter(s)

m – milli- (metric 1/1000)

M – Miniatures

MA – Massachusetts [US state postal designation]

MAAP – Maintenance And Administration Panel

MAC – an MIT interdepartmental lab (stands for many things) (renamed to LCS)

MAC – Media Access Control

MAC – Medium Access Control

MAC – Military Air Command

MACSYMA project MAC’s SYmbolic MAnipulation System

MAD – Mutual Assured Destruction

MADD – Mothers Against Drunk Driving

MAG – Magazine

MAN – Metropolitan Area Network

MAP – Manufacturing Automation Protocol

MAP/TOP Manufacturing Automation Protocol/Technical Office Protocol

MARBI – MAchine Readable form of Bibliographic Information

MARC – MAchine Readable card Catalog

MARS – Multiuser Archival and Retrieval System

MASC – Multiple Award Schedule Contract

MASER – Microwave Amplification by Stimulated Emission of Radiation

MASH – Mobile Army Surgical Hospital

MAST – Multi-Application SOnar Trainer

MAT-CALS – Marine Air Traffic-Control And Landing System

MAU – Math Acceleration Unit

MAU – Media Access Unit

MAU – Medium Access Unit

MB – Manned Base [Space]

MB – MegaByte

MBA – Master Business Administration

MBTA – Massachusetts Bay Transportation Authority

MC – Master of Ceremonies

MCA – Micro Channel Architecture

MCAE – Mechanical Computer Aided Engineering

MCC – Master Control Console

MCC – Microelectronics and Computer technology Corporation

MCC – Mission Control Center [Space]

MCP – Master Control Program

MCP/AS – Master Control Program/Advanced System

MCPO – Master Chief Petty Officer

MCSV – Mars Crew Sortie Vehicle [NASA OEXP]

MD – Doctor of Medicine

MD – Maryland

MD – Maryland [US state postal designation]

MD – Medical Doctor

MD – Months after Date

MDAS – Magnetic Drum Auxiliary Sender

MDC – Metropolitan District Commision (Mass State Agency)

MDE – Modular Design Environment

MDF – Main Distribution Frame [Telephony]

MDRE – Mass Driver Reaction Engine [Space]

MDT – Mean Down Time

ME – Maine

ME – Mechanical Engineer

MECO – Main Engine CutOff [Space, Shuttle]

MEd – Master of EDucation

MERP – Middle-Earth Role Playing

MeV – Million Electron Volts

MF – Medium Frequency (300-3000KHz)

MF – Middle French

MF – Multi-Frequency [Telephony]

MFA – Master Fine Arts

MFA – Museum of Fine Arts [Boston]

MFJ – Modified Final Judgment [Telephony]

MFLOPS – Million FLoating-point OPerations per Second (see also FLOPS)

MFM – Modified Frequency Modulation

MFS – Macintosh File System

MG – Machine Gun

MG – Major General

MG – Military Government

MGH – Massachusetts General Hospital

MGM – Metro-Goldwyn Mayer [Corporate name]

MHD – MagnetoHydroDynamics

MHS – Mail Handling System [ISO]

MHz – Mega HertZ (unit of frequency, 1,000,000 cycles per second)

MI – Michigan

MI – Military Intelligence

MIA – Missing In Action

MIB – Management Information Base

MIDI – Musical Instrument Digital Interface

MIFASS – Marine Integrated Fire And Support System

MILNET – MILitary NETwork

MIM – Morality In Media

MIMD – Multiple Instruction, Multiple Data

MINCE – MINCE Is Not Complete Emacs

MINE – MINE Is Not Emacs (but it is mine)

MIPS – Million Instructions Per Second

Mir – Peace [Russian]

MIRV – Multiple Independently-Targetable Reentry Vehicle

MIS – Management Information System

MIT – Massachusetts Institute of Technology

ML – Middle Latin

mL – milliliter(s)

MLA – Member of Legislative Assembly (see MPP)

MLD – Minimum Lethal Dose

MLL – Mars Logistics Lander [NASA OEXP]

MLS – Microwave Landing System

MLS – Multi-Level Security

MLV – Medium Lift Vehicle [NASA OEXP]

MM – Maryknoll Missioners

mm – millimeters

MMES – Martin Marietta Energy Systems

MMFS – Manufacturing Message Format Standard

MMH – MonoMethyl Hydrazine [Space]

MMM – see 3M

MMT – Multiple Mirror Telescope [Space]

MMU – Manned Maneuvering Unit [Space]

MMU – Memory Management Unit

MMW – Multi-Mega Watt [Space]

MN – Minnesota

MNA – Member of National Assembly (Quebec)

MNP – Microcom Networking Protocol [Corporate name]

MNRAS – Monthly Notices of the Royal Astronomical Society [Space]

MO – Mail Order

MO – Medical Officer

MO – Missouri

MO – Modus Operandi

MO – Money Order

MOC – Mars Observer Camera (on Mars Observer) [Space]

MOD – Ministry of Defence (UK) (sometimes written MoD)

MOL – Manned Orbiting Laboratory [Space]

MOLA – Mars Observer Laser Altimeter (on Mars Observer) [Space]

MOMA – Museum of Modern Art [New York]

MOMV – Manned Orbital Maneuvering Vehicle [Space]

MOR – Middle-Of-the-Road

MOS – Metal Oxide Semiconductor

MOSFET – Metal Oxide Semiconductor Field Effect Transistor

MOTAS – Member Of The Appropriate Sex

MOTIS – Member Of The Inappropriate Sex

MOTIS – Message-Oriented Text Interchange System

MOTOS – Member of the Opposite Sex

MOTSS – Member of the Same Sex

MOTV – Manned Orbital Transfer Vehicle [Space]

MOU – Memorandum Of Understanding

MOUSE – Minimum Orbital Unmanned Satellite of Earth

MP – Melting Point

MP – Member of Parliament

MP – Metropolitan Police

MP – Military Police(man)

MPC – Minor Planets Circular [Space]

MPE – Mission to Planet Earth [Space]

MPG – Miles Per Gallon

MPH – Miles Per Hour

MPP – Member of Provincial Parliament (Canada; also MLA)

MPR – Mars Pressurized Rover [Space]

MPV – Mars Piloted Vehicle [NASA OEXP]

MPW – Macintosh Programmer’s Workshop

MR – Miniatures Rules

MRI – Magnetic Resonance Imaging

MRP – Manufacturing Requirements Planning

MRSR – Mars Rover and Sample Return [Space]

MRSRM – Mars Rover and Sample Return Mission [Space]

MS – ManuScript

MS – Master of Science

MS – Military Science

MS – Motor Ship

MS – Multiple Sclerosis

MSB – Most Significant Bit; Most Significant Byte

MSC – MicroSoft C

MSCP – Mass Storage Control Protocol

MSD – Most Significant Digit

MS-DOS – MicroSoft DOS

MSE – Mobile Subscriber Equipment

MSFC – (George C.) Marshall Space Flight Center (NASA) [Space]

MSFC – Marshall Space Flight Center

MSG – MonoSodium Glutamate

MSH – Marvel Super Heroes

MSL – Mean Sea Level

MSPCA – Massachussetts Society for the Prevention of Cruelty to Animals

MSPE – Mercenaries, Spies & Private Eyes

MSRP – Manufacturer’s Suggested Retail Price

MSS – Management Support System

MSS – ManuScriptS

MSS – Mass Storage System

MSS – Maximum Segment Size [TCP/IP] (see also MTU)

MST – Mountain Standard Time

MT – Metric Ton

MT – Mountain Time

MTA – Message Transfer Agent

MTA – Metropolitan Transportation Authority

MTBF – Mean Time Between Failures

MTC – Man Tended Capability [Space]

MTR – Magnetic Tape Recording

MTSO – Mobile Telephone Switching Office [Telephony]

MTTF – Mean Time To Failure

MTTR – Mean Time To Recovery

MTTR – Mean Time To Repair

MTU – Maximum Transfer Unit [Networking] (see also MSS)

MTV – Music TeleVision

MUF – Maximum Usable Frequency (max freq during sunspot activity)

MULTICS MULTiplex Information Computer Services

MUMPS – Mgh Utility MultiProgram System

MUNG – Mung Until No Good (see the hacker’s dictionary)

MUX – MUltipleXor

MVA – MegaVolt Ampere

MVS – Multiple Virtual Storage [IBM]

MX – Missile eXperimental

N – North

N – Notice

NA – Narcotics Anonymous

NA – North America

NA – Not Applicable

NAACP – National Association for the Advancement of Colored People

NAAS – North American Automated Systems co.

NAB – National Association of Broadcasters

NABISCO NAtional BIScuit COmpany [Corporate name]

NACCIRN North American Coordinating Committee for Intercontinental Research Networking (see also CCIRN)

NACS – National Advisory Committee on Semiconductors

NAD – Network Access Device

NADGE – NATO Air Defense Ground Environment

NAG – Numerical Algorithms Group

NAGE – National Association of Government Employees

NAK – Negative AcKnowledge

NAM – Name and Address Module [Telephony] (cellular phone changeable ROM)

NAM – National Account Manager [Telephony, AT&T]

NAM – Number Assignment Module [Telephony] (cellular phone changeable ROM)

NANP – North American Numbering Plan

NAPAP – National Acid Precipitation Assessment Program

NAR – Nuclear Acoustic Resonance

NARDAC – NAvy Regional Data Automation Center

NAS – National Academy of Sciences

NAS – National Advanced Systems

NASA – National (US) Aeronautics and Space Administration [Space]

NASDA – NAtional (Japan) Space Development Agency [Space]

NASM – National (US) Air and Space Museum [Space]

NASP – National (US) AeroSpace Plane [Space]

NATO – North Atlantic Treaty Organization

NAVDAC – NAVal Data Automation Command

NAVSWC – NAVal Surface Weapons Center

NB – New Brunswick

NB – Nota Bene

NBA – National (US) Basketball Association

NBC – National (US) Broadcasting Company [Corporate name]

NBFM – NarrowBand Frequency Modulation

NBO – Network Build Out

NBS – National Bureau of Standards (renamed NIST) [US Government]

NBVM – Narrow Band Voice Modulation

NC – No Charge

NC – No Connection

NC – North Carolina

NCA – Network Control Analysis

NCC – National (US) Computer Conference

NCC – National (US) Council of Churches

NCDC – National (US) Climatic Data Center

NCE – New Catholic Edition

NCGA – National (US) Computer Graphics Association

NCI – National (US) Cancer Institute [US Government]

NCIC – National (US) Cartographic Information Center

NCO – Non-Commissioned Officer

NCP – Network Control Program

NCR – National (US?) Cash Register [Corporate name]

NCS – Network Computing System

NCSA – National (US) Center for Supercomputing Applications

NCSC – National (US) Computer Security Center [NSA]

NCTL – National Computer and Telecommunications Laboratory

NCV – No Commercial Value

ND – No Date

ND – North Dakota

NDA – Non-Disclosure Agreement

NDDL – Neutral Data Definition Language

NDE – News Development Environment

NDEA – National (US) Defense Education Act

NDL – Network Database Language

NDP – New Democratic Party (Canada)

NDSL – National (US) Defense Student Loan

NDSL – National (US) Direct Student Loan

NDT – Newfoundland Daylight Time

NDV – NASP Derived Vehicle

NDV – NASP Derived Vehicle [Space]

NE – New England

NE – North East

NEAR – National Electronic Accounting and Reporting system

NEARnet New England Academic and Research Network

NEB – New English Bible

NEC – Nippon Electric Company [Corporate name]

NEI – Not Elsewhere Included

NES – National Energy Strategy

NES – Not Elsewhere Specified

NESC – National Energy Software Center

NET – National (US) Educational Television

NET – NETwork

NET – New England Telephone

NEWS – Network extensible Window System

NEXRAD – NEXt generation weather RADar

NF – No Funds

NFC – National (US) Football Conference

NFFE – National (US) Federation of Federal Employees

NFL – National (US) Football League

NFS – Network File System

NG – National Guard

NG – No Good

NGC – New General Catalog [Space]

NH – New Hampshire

NHI – National Health Insurance

NHL – National (Canada) Hockey League

NHLBI – National Heart, Lung, and Blood Institute (Bethesda, MD)

NIC – Network Information Center (“The NIC” is NIC.DDN.MIL)

NICMOS – Near Infrared Camera / Multi Object Spectrometer (HST upgrade) [Space]

NIFTP – (a file transfer network in the UK)

NIH – National (US) Institutes of Health

NIH – Not Invented Here

NIM – Nuclear Instrumentation Module (an electronic instr. standard)

NIMH – National Institute of Mental Health (Rockville, MD)

NIMS – Near-Infrared Mapping Spectrometer (on Galileo) [Space]

NIR – Near InfraRed [Space]

NIS – Network Information System (formerly yp)

NISO – National Information Standards Organization

NIST – National Institute of Standards and Technology (formerly NBS) [US Government]

NJ – New Jersey

NJB – New Jersey Bell [Telephony]

NL – National League (baseball)

NLM – National Library of Medicine

NLP – Natural Language Processing

NLRB – National Labor Relations Board

NLS – Network License Server

NM – Nautical Mile

NM – New Mexico

NM – Night Message

NM – No Mark; Not Marked

NMOS – N channel Metal Oxide Semiconductor (N-MOS) (see MOS)

NMR – Nuclear Magnetic Resonance

NMS – Network Monitoring Station

NNE – North North East

NNTP – Net News Transfer Protocol

NNW – North North West

NNX – NANP syntax for a three-digit string, N:{2-9}, X:{0-9} [Telephony]

NOA – NSWC Office Automation

NOAA – National Oceanic and Atmospheric Administration [Space, US Government]

NOAO – National (Tucson, AZ, US) Optical Astronomical Observatories [Space]

NOC – Network Operations Center

NORAD – NORth American Defense Command

NORM – Naturally Occuring Radioactive Material

NORML – National Organization for the Reform of Marijuana Laws

NOS – Not Otherwise Specified

NOSC – Naval Ocean Systems Center

NOTIS – Network Operator Trouble Information System

NOW – Negotiable Order for Withdrawal [Banking] (Is this MA or NE specific?)

NOx – Nitrogen Oxides

NP – No Protest

NP – Nondeterministic-Polynomial

NP – Notary Public

NP – Noun Phrase

NPA – Numbering Plan Area (area code) [Telephony]

NPC – Non-Player Character (see PC) [Role-playing]

NPL – National Physical Laboratory (UK)

NPL – Non-Procedural Language

NPN – Negative-Positive-Negative (transistor)

NPN – NonProtein Nitrogen

NPR – National Public Radio

NPR – non-Processor Request [PDP11, UNIBUS]

NQS – Network Queuing System

NRA – National Reconstruction Act (FDR era US)

NRA – National Rifle Association

NRAO – National Radio Astronomical Observatory [Space]

NRC – National Research Council

NRC – Nuclear Regulatory Commission

NRE – Non-Recurring Engineering (as in NRE costs)

NREN – National (US) Research and Education Network

NRL – Naval Research Labs

NRO – National Reconnaissance Office

NRO – National Reconnaissance Organization [Space]

NRZ – Non-Return to Zero

NRZI – Non-Return to Zero Inverted (magnetic tape, 800 bpi)

NS – Neutron Star [Space]

NS – Not Specified

NS – Nova Scotia

NS – Nuclear Ship

NSA – National Security Agency [US Government]

NSAP – Network Service Access Point [OSI, Networking]

NSC – National (US) Security Council [US Government]

NSE – Network Software Environment

NSF – National (US) Science Foundation [US Government]

NSS – Nodal Switching System [NSFnet]

NSSDC – National Space Science Data Center [Space]

NST – Newfoundland Standard Time

NSTS – National Space Transportation System [Space]

NSW – New South Wales (Australia)

NSWC – Naval Surface Warfare Center

NSWC – Naval Surface Weapons Center

NT – New Testament

NT – Newfoundland Time

NT – Northern Territory

NTEU – National Treasury Employees Union

NTIS – National Technical Information Service

NTN – Neutralized Twisted Nematic

NTP – Network Time Protocol [Internet]

NTP – Normal Temperature and Pressure (see STP)

NTSB – National Transportation Safety Board [US Government]

NTSC – National Television Standards Committee

NTSC – Never Twice Same Color

NTT – New Technology Telescope [Space]

NTT – Nippon Telephone & Telegraph

NU – Name Unknown

NURBS – NonUniform Rational B-Spline

NUSC – Naval Underwater Systems Center [US Government]

NV – Nevada

NW – North West

NWNET – NorthWestNet

NWS – National Weather Service

NWT – North West Territories (Australia)

NXX – NANP syntax for a three-digit string, N:{2-9}, X:{0-9} [Telephony]

NY – New York

NYC – New York City

NYNEX – New York and New England (Telephone)

NYPD – New York Police Department

NYSE – New York Stock Exchange

NYSERNet – New York State Educational and Research Network

NZ – New Zealand

NZUSUGI New Zealand Unix System User Group, Inc.

OA – Office Automation

OA – Overeaters Anonymous

OAO – Orbiting Astronomical Observatory [Space]

OAS – Organization of American States

OATS – Office Automation Technology and Services

OBE – Order of the British Empire

OBS – Omni Bearing Selector

OC – Order of Canada

OCDM – Office of Civil Defense and Mobilization

OCI – Out of City Indicator

OCLC – Online Computer Library Center, Inc.

OCLC – Online Computer Library Center (Ohio College Library Catalog)

OCO – Object Code Only

OCR – Optical Character Recognition

OCS – Officer Candidate School

OCST – Office of Commercial Space Transportation [Space]

OD – Doctor of Optometry

OD – Oculus Dexter (right eye)

OD – Officer of the Day

OD – OverDose

ODI – Optical Digital Image

ODISS – Optical Digital Image Storage System

ODT – Octal Debugging Technique

ODT – Online Debugging Technique

OE – Old English

OED – Oxford English Dictionary

OEM – Original Equipment Manufacturer

OEO – Office of Economic Opportunity

OES – Order of the Eastern Star

OEXP – Office of Exploration [NASA]

OF – Old French

OFM – Order of Friars Minor

OFS – Order of Free State

OG – Original Gum

OH – Ohio

OIRA – Office of Information and Regulatory Affairs

OIU – Office Interface Unit

OJT – On the Job Training

OLTP – On-Line Transaction Processing

OMB – Office of Management and Budget [US Government]

OMD – Orchestral Manouevers in the Dark

OMS – Orbital Maneuvering System [Space]

OMV – Orbital Maneuvering Vehicle [Space]

ON – Old Norse

ONC – Open Network Computing

ONI – Office of Naval Intelligence

ONI – Operator Number Identification [Telephony]

ONR – Office of Naval Research

OOP – Object Oriented Programming

OOPART – Out Of Place ARTifact

OOPS – Object-Oriented Programming System

OP – Observation Post

OP – OFFICEPOWER office automation system, trademark of CCI

OP – Order of Preachers

OP – Out of Print

OPEC – Organization of Petroleum Exporting Countries

OPF – Orbiter Processing Facility [Space]

OPM – Office of Personnel Management

OPUS – Obvious Password Utility System (Eugene Spafford <Spaf@Purdue.Edu>)

OR – Operating Room

OR – Oregon

OR – Owner’s Risk, Own Risk

ORFEUS – Orbiting and Retrievable Far and Extreme Ultraviolet Spectrometer [Space]

ORNL – Oak Ridge National Laboratory

OROM – Optical Read Only Memory

OS – Oculus Sinister (left eye)

OS – Operating System

OS – Ordinary Seaman

OS – Out of Stock

OSB – Order of St. Benedict

OSC – Orbital Sciences Corporation [Space]

OSCAR – Orbiting Satelite Carry Amateur Radio (1st launched 12 Dec 1961)

OSCAR – Orbiting Satellite Carry Amateur Radio (1st launched 12 Dec 1961)

OSCAR – Orbiting Satellite Carrying Amateur Radio [Space]

OSCRL – Operating System Command Response Language

OSD – Office of the Secretary of Defense

OSDIT – Office of Software Development and Information Technology

OSF – Open Software Foundation

OSF – Open Systems Foundation

OSF – Order of St. Francis

OSHA – Occupational Safety and Health Administration [US Government]

OSI – Office of Scientific Integrity [NIH]

OSI – Open Systems Interconnection (per ISO; 7 layer model)

OSI/RM – Open Systems Interconnection/Reference Model

OSME – Open Systems Message Exchange

OSP – Optical Storage Processor

OSPFIGP Open Shortest-Path First Internal Gateway Protocol [Internet]

OSS – Office of Strategic Services (later CIA)

OSS – Office Support System

OSS – Operation Support System [Telephony, AT&T]

OSSA – Office of Space Science and Applications [Space]

OSSE – Oriented Scintillation Spectrometer Experiment (on GRO) [Space]

OSTP – Office of Science and Technology Policy

OSTP – (White House) Office of Science and Technology Policy [US Government]

OT – Old Testament

OT – OverTime

OTA – Office of Technical Assistance

OTA – Office of Technology Assessment

OTA – Optical Telescope Assembly (on HST) [Space]

OTB – Off-Track Betting

OTC – Over The Counter (stocks)

OTF – Open Token Foundation

OTH-B – Over The Horizon – Backscatter (as in radar)

OT&LF – Open Taxi & Limousine Foundation

OTR – On The Rag

OTS – Officers’ Training School

OTV – Orbital Transfer Vehicle [Space]

OUTWATS OUTward Wide Area Telephone Service [Telephony]

OV – Orbital Vehicle [Space]

OV – Orbiter Vehicle [Space]

PA – Pennsylvania

PA – Per Annum

PA – Play Aid

PA – Power of Attorney

PA – Press Agent

PA – Private Account

PA – Public Address

PA – Purchasing Agent

PABX – Private Automatic Branch eXchange [Telephony]

PACCOM – Pacific Computer Communications network consortium [Networking]

PACX – Private Automatic Computer eXchange

PAD – Packet Assembler-Disassembler [Networking]

PAH – Polycyclic Aromatic Hydrocarbon

PAL – Phase Alternation Line-rate

PAL – Programmable Array Logic

PAM – Payload Assist Module [Space]

PAM – Pulse Amplification Modulation

PARC – Palo Alto Research Center, xerox

PASS – Personal Access Satellite System [NASA]

PATROL – Program for Administrative Traffic Reports On Line

PBM – Play By Mail game

PBS – Public Broadcasting System

PBX – Private Branch eXchange [Telephony]

PC – Peace Corps

PC – PerCent; PerCentage

PC – Personal Computer (IBM wants you to believe a specific kind)

PC – Player Character (see NPC) [Role-playing]

PC – Post Card

PC – Post Cibum (after meals)

PC – Privileged Character

PC – Privy Council

PC – Program Counter

PC – Progressive Conservative party [Canada]

PC – Providence College

PC/AT – Personal Computer/Advanced Technology

PCB – PolyChlorinated Biphenyl

PCB – Printed Circuit Board

PC-DOS – Personal Computer DOS

PCI – Panel Call Indicator

PCIE – President’s Council on Integrity and Efficiency

PCL – Printer Command Language

PCM – Plug-Compatible Mainframe

PCM – Pulse Code Modulation

PCPC – Personal Computers Peripheral Corporation

PCS – Permanent Change of Station

PCTE – Portable Common Tools Environment

PCTS – Posix Conformance Test Suite

PD – Per Diem

PD – Police Department

PD – Potential Difference

PD – Public Domain

PDAD – Proposed Draft ADdendum

PDE – Partial Differential Equation

PDES – Product Data Exchange Specifications

PDF – Program Development Facility

PDL – Page Description Language

PDL – Program Design Language

PDN – Public Data Network

PDP – Plasma Display Panel

PDP – Programmed Data Processor

PDP – Programmed Data Processor [DEC]

PDQ – Pretty Damned Quick

PDS – Premises Distribution System [AT&T]

PDT – Pacific Daylight Time

PE – Phase Encoded

PE – Physical Education

PE – Prince Edward island

PE – Printer’s Error

PE – Professional Engineer

PE – Protestant Episcopal

PEI – Prince Edward Island

PEP – Productivity Enhancement Project

PEPE – Pepe Est Presque Emacs

PERL – Pathologically Eclectic Rubbish Lister

PERL – Practical Extraction and Report Language

PEX – Phigs/phigs+ Extension to X

PFC – Plasma Fusion Center [MIT]

PG – Parental Guidance (suggested) [Movie rating]

PGA – Professional Graphics Adapter

PGA – Pure Grain Alcohol

PHA – Pulse Height Analyzer (or Analysis)

PHIGS – Programmers Hierarchical Interactive Graphics System

PHS – Public Health Service

PhysRev – Physical Review Journal

PI – Principal Investigator

PI – Priority Interrupt

PI – Private Investigator

PIC – Plastic/Polyethelene Insulated Cable [Telephony]

PIC – Position Independant Code

PIF – Paid In Full

PIT – Principal, Interest, and Taxes

PIXEL – PIcture ELement

PLA – Programmable Logic Array

PLATO – Programmed Learning for Automated Teaching Operations (U. Ill., early ’70s)

PLC – Programmable Logic Controller

PLCC – Plastic Leaded Chip Carrier

PLL – Phase-Locked Loop

PLM – Programming Language for Microcomputers

PLO – Palestine (sic?) Liberation Organization (?)

PLO – Please Leave On

PLSS – Portable Life Support System [Space]

PM – PayMaster

PM – Police Magistrate

PM – Post Meridiem

PM – Post Meridiem (after noon)

PM – PostMaster

PM – PostMortem

PM – Pressurized Module [Space]

PM – Preventive Maintenance

PM – Prime Minister

PM – Provost Marshal

PMC – Permanently Manned Capability [Space]

PMIRR – Pressure Modulated InfraRed Radiometer (on Mars Observer) [Space]

PMO – Prime Minister’s Office

PMOS – P channel Metal Oxide Semiconductor (P-MOS) (see MOS)

PMS – PreMenstrual Syndrome

PMT – PhotoMultiplier Tube

PM/X – Presentation Manager for X windows

PN – Promissory Note

PNP – Positive-Negative-Positive (transistor)

PO – Petty Officer

PO – Post Office

PO – Postal Order

PO – Purchase Order

POC – Port Of Call

POD – Pay On Delivery

POE – Port Of Embarkation

POE – Port Of Entry

POGO – Polar Orbiting Geophysical Observatory

POM – Phase Of Moon

POP – Point of Presence [Telephony]

POP – Post Office Protocol [Networking] (esp. TCP/IP)

POPS – Paperless Order Processing System

POR – Price On Request

POS – Point Of Sale

POS – Professional Operating System [DEC]

POSI – Promoting conference for OSI

POSIX – Portable Operating System for unIX

POSIX – Portable Operating System Interface

POTS – Plain Old Telephone Service [Telephony]

POTV – Personnel Orbit Transfer Vehicle [Space]

POV – Point Of View

POW – Prisoner Of War

PP – Parcel Post

PP – Past Participle

PP – Post Pay (payphone) [Telephony]

PP – Primary Point

PPB – Parts Per Billion

PPC – Pour Prendre Conge’ (to take leave)

PPCS – Person to Person, Collect, Special [Telephony]

PPM – Parts Per Million

PPN – Parameterized Post-Newtonian formalism for general relativity

PPN – Project Programmer Number

PPP – Point-to-Point Protocol (successor to SLIP (q.v.))

pps – Packets per Second

PPS – PostPostScriptum

PPT – Parts Per Trillion

PPT – Pulse Pair Timing

PPT – Punched Paper Tape

PQ – Province of Quebec

PR – PayRoll

PR – Public Relations

PR – Puerto Rico

PRC – Planning Research Corporation

PREPnet Pennsylvania Research & Economic Partnership Network

PRI – Primary Rate Interface (ISDN) [Telephony]

PRN – pro re nata [Medicine] (as needed?)

PROFS – PRofessional OFfice System [IBM]

PROM – Programmable Read-Only Memory

PS – PicoSecond

PS – PostScript

PS – PostScriptum

PS – Power Steering

PS – Power Supply

PS – Proposed Standard

PS – Public School

PSA – Problem Statement Analyzer

PSC – Pittsburgh Supercomputer Center

PSC – Polar Stratospheric Clouds

PSDN – Public Switched Data Network [Telephony]

PSDS – Public Switched Digital Service [Telephony, AT&T]

PSE – Programming Support Environment

PSF – Point Spread Function [Space]

PSG – Platoon SerGeant

PSI – Performance Systems International [Corporate name, Networking]

PSI – Power Systems, Incorporated [Corporate name, Model Railroading]

PSK – Phase Shift Keying

PSL – Problem Statement Language

PSN – Packet Switch Node [ARPANET/MILNET] (replaced IMP)

PSR – Product Specific Realizations

PSR – PulSaR [Space]

PSS – (unknown to me, but something in the UK environment)

PST – Pacific Standard Time

PSTN – Public Switched Telephone Network

PT – Pacific Time

PT – Patrol Torpedo (as in PT boat)

PT – Physical Therapy

PT – Physical Training

PTA – Parent-Teacher Association

PTD – Parallel Transfer Disk

PTL – Praise The Lord (ministry)

PTN – Plant Test Number [Telephony] (actual number assigned for 800 service)

PTO – Patent and Trademark Office

PTO – Please Turn Over

PTO – Power Take-Off

PTT – Post, Telephone and Telegraph administration

PTV – Passenger Transport Vehicle [Space]

PUC – Public Utilities Commision

PV – Photovoltaic [Space]

PVC – Permanent Virtual Circuit (see also VC)

PVC – Poly-Vinyl Chloride

PVO – Pioneer Venus Orbiter [Space]

PW – Prisoner of War (usually POW)

PWG – Permanent Working Group

PX – Post eXchange (see BX)

QAM – Quadrature Amplitude Modulation

QC – Quality Control

QC – Queen’s Counsel (KC when queen reigning)

QD – Quaque Die (daily) [Medicine]

QDA – Quantity Discount Agreement

QED – Quod Erat Demonstrandum (which was to be demonstrated) [Latin]

QEF – Quod Erat Faciendum (which was to be done) [Latin]

QEI – Quod Erat Inveniendum (which was to be found out) [Latin]

QET – Quantum Effect Transistor

QIC – Quarter-Inch Cartridge

QID – Quater In Die (four times a day) [Medicine]

QLI – Query Language Interpreter

QM – QuarterMaster

QMC – QuarterMaster Corps

QMF – Query Management Facility

QMG – QuarterMaster General

QMS – Quality Micro Systems [Corporate name]

QNS – Quantity Not Sufficient

QSO – Quasi-Stellar Object [Space]

q.v. – ???? (Latin(?): which see)

QWERTY – first six keys from left on top alphabetic row of standard keyboard

R – Restricted [Movie rating]

R – Rolemaster

RA – Regular Army

RA – Research Assistant

RA – Royal Academy

RAAF – Royal Australian Air Force

RACE – Random Access Card Equipment

RACEP – Random Access and Correlation for Extended Performance

RAD – Radiation Absorbed Dose

RAD – Rapid Access Disk

RADAR – RAdio Detection And Ranging

RADM – Rear ADMiral

RAF – Royal Air Force

RAM – Random Access Memory (R/W)

RAM – Red Academicia de Mexico (Mexican Academic Network)

RARDE – Royal Armaments Research and Development Establishment

RARE – R’eseaux Associ’es pour la Recherche Europ’eenne (the European Organization of Research Networks)

RAS – Reliability, Availability, and Serviceability

RASC – Residence Account Service Center

RATS – Radio Amateur Telecommunications Society

R&B – Rhythm and Blues (commonly R and B)

RBC – Red Blood Count

RBI – Runs Batted In

RBOC – Regional Bell Operating Company

RC – Red Cross

RC – Regional Center

RC – Resistor-Capacitor circuit (as in filters)

RC – Roman Catholic

RCA – Radio Corporation of America [Corporate name]

RCAF – Royal Canadian Air Force

RCAS – Reserve Component Automation System

RCC – Radio Common Carrier

RCMP – Royal Canadian Mounted Police

RCS – Reaction Control System [Space]

R&D – Research and Development (commonly R and D)

RD – Rural Delivery

RDA – Remote Data Access

RDBMS – Relational DataBase Management System

RDF – Radio Direction Finding

REA – Rail Express Agency

RECON – Reconnaissance

REM – Rapid Eye Movement

REO – R. E. Olds

REO – Removable, Erasable, Optical

RETMA – Radio {something(equipment?)?} {something?} Manufacturers’ Association (????)

REXX – Restructured EXtended eXecutor

RF – Radio Frequency

RF – Radio Frequency [Space]

RFC – Request For Comments (ala ARPA Internet)

RFD – Rehoboth (MA) Fire Department

RFD – Rural Free Delivery

RFI – Radio Frequency Interference

RFI – Radio Frequency Interference [Space]

RFP – Request for Proposal

RFQ – Request for Quote

RFS – Remote File System

RGB – Red Green Blue

RGP – Raster Graphics Processor

RH – Right Hand

RHC – Regional (Bell) Holding Company

RHS – Right Hand Side

RI – Rhode Island

RIACS – Research Institute for Advanced Computer Science (NASA)

RIACS – Research Institute for Advanced Computer Science [Space]

RIAS – Radio In the American Sector, berlin

RIF – Reading Is Fundamental

RIF – Reduction In Force

RILM – Repertoire International de Literature Musicale

RIP – Rest In Peace (or Requiescat In Pace : latin)

RIP – Routing Interchange Protocol

RIPE – R’eseaux IP Europ’eenne (European IP Networks) (of RARE, q.v.)

RISC – Reduced Instruction Set Computer

RITA – Recognition of Information Technology Achievement award

RJE – Remote Job Entry

RLC – Resistor Inductor Capacitor

RLG – Research Libraries Group

RLIN – Research Libraries Information Network (run by RLG (q.v.))

RLL – Run Length Limited

RMA – Radio Manufacturers’ Association

RMA – Return Materials Authorization

RMATS – Remote Maintenance Administration and Traffic System [Telephony]

RMS – Remote Manipulator System [Space]

RMS – Richard M. Stallman

RMS – Root Mean Square

RMS – Royal Mail Ship

RN – Registered Nurse

RN – Royal Navy

RNA – RiboNucleic Acid

RNGC – Revised New General Catalog [Space]

RNZAF – Royal New Zealand Air Force

ROFF – Run-OFF

ROG – Receipt Of Goods

ROM – Range Of Motion [Medicine]

ROM – Read-Only Memory

ROM – Rupture Of Membrane (as in birth)

ROSAT – ROentgen SATellite [Space]

ROSE – RATS (q.v.) Open Systems Environment

ROSE – Remote Operations Service Entity (per ISO/CCITT layer 7)

ROTC – Reserve Officers’ Training Corps

ROTS – Rotary Out Trunks Selectors

ROYGBIV Red, Orange, Yellow, Green, Blue, Indigo, Violet

RPC – Remote Procedure Call

RPG – RePort Generator

RPG – Role Playing Game

RPI – Rensselaer Polytechnic Institute

RPM – Revolutions Per Minute

RPN – Reverse Polish Notation

RPO – Railway Post Office

RPS – Revolutions Per Second

RPV – Remotely Piloted Vehicle

RQ – RuneQuest

RR – RailRoad

RR – Route Relay

RR – Rural Route

RRO – Rate and Route Operator [Telephony]

RS – Recommended Standard (EIA)

RS – Recording Secretary

RS – Revised Status

RS – Right Side

RS – Royal Society

RSCS – Remote Spooling Communications Subsystem

RSFSR – Russian Soviet Federated Socialist Republic

RSN – Real Soon Now

RSU – Remote Switching Unit

RSV – Revised Standard Edition

RSVP – Repondez S’il Vous Plait (please reply)

RSWC – Right Side up With Care

RT – RadioTelephone

RT – RealTime

RTA – Remote Trunk Arrangement [Telephony]

RTAC – Regional Technical Assistance Center [Telephony]

RTF – Rich Text Format

RTFM – Read The @!# Manual

RTFM – Read The F***ing Manual

RTG – Radioisotope Thermoelectric Generator

RTG – Radioisotope Thermoelectric Generator [Space]

RTLS – Return To Launch Site (Shuttle abort mode) [NASA, Shuttle, Space]

RTR – Ready to Run [Model Railroading]

RTR – Reel-To-Reel

RTS – Request To Send (EIA RS-232-C)

RTTY – Radio Teletype

RU – Receive Unit

RVD – Remote Virtual Disk [MIT]

RW – Right Worshipful

RW – Right Worthy

RX – Receive

Ry – Railway

S – South

S – Supplement

SA – Salvation Army

SA – Seaman Apprentice

SA – Service Assistant

SA – Sex Appeal

SA – Sine Anno (without date)

SA – South Africa

SA – South America

SA – Subject to Approval

SAA – South Atlantic Anomaly

SAA – South Atlantic Anomaly [Space]

SAA – Systems Application Architecture

SAC – Special Area Code [Telephony] (represent services, not places)

SAC – Strategic Air Command (see TAC)

SAC – Strategic Air Command [US military]

SADD – Students Against Drunk Driving

SAFENET Survivable Adaptable Fiberoptic Embedded Network [US Navy]

SAM – Surface to Air Missile

SAM – Surface-to-Air Missile

SAMA – Step-by-step Automatic Message Accounting [Telephony]

SAMPEX – Solar Anomalous and Magnetospheric Particle EXplorer [Space]

SAMTO – Space And Missile Test Organization [Space]

SAO – Smithsonian Astrophysical Observatory [Space]

SAP – Second Audio Program

SAP – Service Access Point [OSI, Networking]

SAR – Search And Rescue

SAR – Synthetic Aperture Radar

SARA – Satellite pour Astronomie Radio Amateur [Space]

SARA – Stichting Academisch Rekencentrum Amsterdam (Amsterdam Universities Computing Center)

SAREX – Search and Rescue Exercise [Space]

SAREX – Shuttle Amateur Radio Experiment [Space]

SARTS – Switched Access Remote Test System

SAS – Small Astronomy Satellite

SAS – Space Activity Suit [Space]

SASE – Self-Addressed Stamped Envelope

SASI – Shugart Associates Systems Interface

SAT – Satellite [Space]

SAW – Surface Acoustic Wave

SBA – Small Business Administration

SC – Secondary Channel

SC – Sectional Center

S&C – Skull & Crossbones

SC – South Carolina

S/C – SpaceCraft [Space]

SC – SubCommittee

SCA – Shuttle Carrier Aircraft [Space]

SCAD – Subsonic Cruise Armed Decoy

SCADC – Standard Central Air Data Computer

SCAME – SCreen oriented Anti-Misery Editor

SCAMP – Single-Chip A-series Mainframe Processor

SCAN – Switched Circuit Automatic Network

SCC – Specialized Common Carriers

SCC – Switching Control Center

SCCS – Source Code Control System

SCE – Signal Conversion Equipment

SCE – Structure Chart Editor

SCI – SpaceCraft Incorporated

SCIFI – SCIence FIction (often used pejoratively of what really isn’t)

SCO – Santa Cruz Operation

SCOOPS – SCheme Object Oriented Programming System

SCOTS – Surveilance and Control Of Transmission Systems

SCSI – Small Computer Systems Interface

SCT – Schmidt-Cassegrain Telescope [Space]

SCUBA – Self Contained Underwater Breathing Apparatus

SCUD – Subsonic Cruise Unarmed Decoy

SD – South Dakota

SDB – Source(?) DeBugger

SDI – Standard Disk Interconnect [DEC]

SDI – Strategic Defense Initiative [Space, US Government]

SDIO – Strategic Defense Initiative Organization [Space, US Government]

SDLC – Synchronous Data Link Control [IBM]

SDM – Sub-rate Data Multiplexer

SDN – Software Defined Network [Telephony, AT&T]

SDN – System Development Network (Korea)

SDO – Staff Duty Officer

SDSC – San Diego Supercomputer Center

SDV – Shuttle Derived Vehicle [Space]

SE – Service Engineer (see also CE, FE)

SE – South East

SEATO – SouthEast Asia Treaty Organization

SEC – Security Exchange Commission

SECNAV – SECretary of the NAVy

SED – Stream EDitor

SEI – Software Engineering Institute (Carnegie Mellon)

SEI – Space Exploration Initiative [Space]

SEL – Software Engineering Laboratory

SEM – Scanning Electron Microscope

SEST – Swedish-European Submillimeter Telescope [Space]

SETI – Search for Extra Terrestrial Intelligence [Space]

SETI – Search for ExtraTerrestrial Intelligence [Space]

SF – San Francisco

SF – Science Fiction; Speculative Fiction

SF – Standard Form

SF – Star Frontiers

SFRPG – Science Fiction Role Playing Game

SG – StarGuard

SG – SubGroup

SGML – Standard Generalized Markup Language

SHAPE – Supreme Headquarters Allied Powers Europe

SHAR – SHell ARchiver

SHCD – Sherlock Holmes Consulting Detective

SHF – Super High Frequency (3-30GHz)

SHRPG – Super Hero Role Playing Game

SI – Staten Island

SIAM – Society for Industrial and Applied Mathematics

SID – Sudden Ionospheric Disturbance [Space]

SIG – Special Interest Group

SIGCAT – Special Interest Group for Cd-rom Applications Technology

SIMD – Single Instruction, Multiple Data

SIMM – Single In-line Memory Module

SIMM – System Integrated Memory Module

SINE – SINE is not EINE

SIPS – Satellite Imagery Processing System

SIR – Shuttle Imaging Radar [Space]

SIRTF – Space (formerly Shuttle) InfraRed Telescope Facility [Space]

SIRTF – Space Infrared Telescope Facility [Space]

SIS – Strategic Information System

SISCOM – Satellite Information System COMpany

SITA – Societe Internationale Telecommunications Aeronautiques

SJ – Society of Jesus

Skyhook Surface to space “elevator” transportation system [Space]

SL – Salvage Loss

SL – Space Launch [Space]

SL – SpaceLab [Space]

SLA – Special Libraries Association

SLA – Synchronous Line Adapter

SLAC – Stanford Linear Accelerator Center

SLAN – Sine Loco, Anno, (vel) Nomine (without place, year, or name)

SLAR – Side Looking Airborne Radar

SLAR – Side-Looking Airborne Radar [Space]

SLBM – Submarine Launched Ballistic Missiles

SLC – Space Launch Complex [Space]

SLC – Subscriber Loop Carrier [Telephony]

SLDC – Synchronous Data Link Control

SLIP – Serial Line Internet Protocol

SLIP – Serial Line IP (sometimes SL/IP) (see also PPP)

SLP – Super Long Play (VHS VCR)

SLS – Space(lab) Life Sciences [Space]

SM – Service Mark

SMA – Sergeant Major of the Army

SMA – Spectrum Manufacturers Association

SMC – Small Magellanic Cloud (see LMC)

SMC – Small Magellanic Cloud [Space]

SMD – Storage Module Device (interface standard for disk drives)

SMD – Surface Mounted Devices

SMDR – Station Message Detail Recording [Telephony]

SMDS – Switched Multi-megabit Data Service [Telephony, Networking]

SME – Solar Mesosphere Explorer [Space]

SMEGMA – Sophisticated Modern Editor with Gloriously Magnificent Abilities

SMERSH – Abbr. of Russian phrase meaning “Death to the spies.”

SMEX – SMall EXplorers [Space]

SMILS – Sonobuoy Missile Impact Location System

SMM – Solar Maximum Mission (satellite 1980-1989) [Space]

SMTP – Simple Mail Transfer Protocol

SMU – Southeastern Massachusetts University

SMU – Southern Methodist University

SN – Science News [Periodical]

SN – Serial Number

SN – Super Nova

SN – SuperNova (e.g., SN1987A) [Space]

SNA – Systems Network Architecture [IBM]

SNADS – SNA Distribution Services

SNAFU – Situation Normal — All Fouled Up (also more profane versions)

SNAP – Shipboard Non-tactical Automated data Processing program

SNAP – Sub Network Access Protocol [OSI, Networking]

SNCF – Societe National des Chemins de Fer (French National Railways)

SNF – Server-Natural Format

SNMP – Simple Network Management Protocol [TCP/IP]

SNOBOL – StriNg Oriented symbOLic Language

SNPA – SubNetwork Point of Attachment

SNR – Signal to Noise Ratio

SNR – Signal to Noise Ratio [Space]

SNR – SuperNova Remnant [Space]

SNU – Solar Neutrino Units [Space]

SO – Seller’s Option

SO – Significant Other

SO – Space Opera

SO – Strike Out

SOAP – Symbolic Optimizing Assembler Program

SOFIA – Stratospheric Observatory For Infrared Astronomy [Space]

SOH – Start Of Header, ASCII control character (dec=01,control-A)

SOHIO – Standard Oil of oHIO [Corporate name]

SOHO – SOlar Heliospheric Observatory [Space]

SOL – Short on Landing (or, colloquially, Shit Out of Luck)

SONAR – SOund Detection And Ranging

SONET – Synchronous Optical Network [Telephony]

SOP – Standard Operating Procedure

SOS – Save Our Souls (International standard distress call, Morse …—…)

SOS – Silicon On Sapphire

SOS – Son of Stopgap (editor) [DEC]

SP – Shore Patrol

SP – Short Play (VHS VCR)

s.p. – sine prole (Latin: without issue) [Genealogy]

SP – Southern Pacific [Corporate name, Railroading]

SP – Stack Pointer

SP – Star Patrol

SPA – Software Publishers Association

SPAG – Standards Promotion and Applications Group

SPAN – Space Physics and Analysis Network [NASA] (DECnet)

SPAN – Space Physics and Analysis Network [Space]

SPAR – Stock Points Adp Replacement

SPARC – Scalable Processor ARChitecture

SPARC – Standards, Planning, And Requirements Committee

SPAWAR – naval SPAce and WARfare command

SPC – Software Productivity Consortium

SPCA – Society for the Prevention of Cruelty to Animals

SPCC – Society for the Prevention of Cruelty to Children

SPDM – Special Purpose Dextrous Manipulator [Space]

SPEC – Systems Performance Evaluation Cooperative

SPITBOL SPeedy ImplemenTation of snoBOL

SPNI – Society for the Protection of Nature in Israel

SPOT – Systeme Probatoire pour l’Observation de la Terre [Space]

SPS – Solar Power Satellite [Space]

SPUR – Systech Pluraxial Unplug Repeater

SQE – Signal Quality Error (IEEE 802.3, eqv to D/I/X “Collision Presence Test”) [Ethernet]

SQIID – Simultaneous Quad Infrared Imaging Device (at NOAO)

SQL – Structured Query Language

SQUID – Superconducting QUantum Interference Device

SRAM – Short Range Attack Missile

SRAM – Static RAM

SRB – Solid (fuel) Rocket Booster [Space]

SRG – Short and Ring Ground (test) [Telephony]

SRI – Stanford Research Institute

SRM – Solid Rocket Motor [Space]

SRO – Standing Room Only

SS7 – Signalling System #7 [Telephony]

SSA – Social Security Administration [US Government]

SSB – Single Side Band

SSC – Superconducting Super Collider

SSE – South-SouthEast

SSF – Space Station Fred (er, Freedom) [Space]

SSF – Space Station Freedom [NASA, Space]

SSFF – Showcase Software Factory of the Future

SSG – Staff SerGeant

SSI – Small Scale Integration

SSI – Solid-State Imager (on Galileo) [Space]

SSI – Space Services Incorporated [Corporate name, Space]

SSI – Space Studies Institute [Space]

SSI – Supplemental Security Income

SSME – Space Shuttle Main Engine [Space]

SSPF – Space Station Processing Facility [Space]

SSPS – Satellite Solar Power Station [Space]

SSR – Secondary Surveillance Radar

SSR – Soviet Socialist Republic

SSRMS – Space Station Remote Manipulator System [Space]

SST – Spectroscopic Survey Telescope [Space]

SST – SuperSonic Transport [Space]

SSTO – Single Stage To Orbit [Space]

SSTV – Slow Scan TeleVision

SSW – South-SouthWest

ST – Short Ton

STARS – Software Technology for Adaptable, Reliable Systems

STD – Sacrae Theologiae Doctor (doctor of sacred theology)

STD – Sexually Transmitted Disease (replaces VD)

STD – State Transition Diagram

STD – Subscriber Trunk Dialing (British, and elsewhere; equiv. DDD in USA)

STI – Standard Tape Interconnect [DEC]

STILO – Scientific and Technical Intelligence Liaison Office

STIS – Space Telescope Imaging Spectrometer (to replace FOC and GHRS) [Space]

STL – St. Louis (airport designation)

STN – SuperTwisted Nematic

STOL – Short TakeOff and Landing

STP – Shielded Twisted Pair [Telecom, Networking]

STP – Software Through Pictures

STP – Standard Temperature and Pressure (see NTP)

STRPG – Star Trek: The Role-Playing Game

STS – Space Transportation System (space shuttle) [NASA]

STScI – Space Telescope Science Institute [Space]

STV – Single Transferable Vote

STV – Space Transfer Vehicle [Space]

SUM – Symantec Utilities for Macintosh

SUN – Stanford University Network

SUN – SUN MicroSystems Computer (not an Acronym) [Corporate name]

SUNOCO – SUN Oil COmpany [Corporate name]

SUNY – State University of New York

SURAnet Southeastern Universities Research Association Network

SVID – System V Interface Definition

SW – South West

SW – SuperWorld

SWAS – Submillimeter Wave Astronomy Satellite [Space]

SWBT – South Western Bell Telephone [Telephony]

SWF – ShortWave Fading [Space]

SWIFT – Society for Worldwide Interbank Financial Communications

SWS – Scientific Workstation Support

SXS – Step by Step switching [Telephony]

T – Traveler

T1 – 1.544Mbps [Telephony], one of the basic signalling systems 24x64Kb

T3 – 45Mbps (eq 28 T1 channels) [Telephony]

TA – Teaching Assistant

TAC – Tactical Air Command (see SAC)

TAC – Terminal Access Controller [ARPANET/MILNET] (replaced TIP)

TACACS – Terminal Access Controller Access Control System [ARPANET/MILNET]

TACCS – Tactical Army Combat service support Computer System

TAE – Transportable Applications Environment

TAL – Trans-Atlantic Abort Landing [NASA, Shuttle]

TAL – Transatlantic Abort Landing (Shuttle abort plan) [Space]

TANSTAAFL – There Ain’t No Such Thing As A Free Lunch

TAR – Tape ARchiver

TASI – Time Assign{ment,ed} Speech Interpolation [Telephony]

TAU – Thousand Astronomical Units [Space]

TB – TuBerculosis

TBA – To Be Announced

TBD – To Be Determined

TBD – To Be Done

TC – Teachers College

TCA – Terminal Controlled Airspace

TCP – Transmission Control Protocol

TCP/IP – Transmission Control Protocol/Internet Protocol

TCS – Thermal Control System [Space]

TCSEC – Trusted Computer System Evaluation Criteria (orange book)

TCT – To Challenge Tomorrow

TD – Tardive Dyskinesia

TD – TouchDown

TD – Treasury Department

TDCC – Transportation Data Coordinating Committee

TDE – Transition Diagram Editor

TDI – Trusted Database Interpretation

TDM – Time-Division Multiplexer

TDR – Time Domain Reflectometer

TDRS – Tracking and Data Relay Satellite [Space]

TDRSS – Tracking and Data Relay Satellite System [Space]

TDY – Temporary DutY

TECO – Tape Editor and COrrector

TECO – Text Editor and COrrector

TEFLON – polyTEtraFLuOrethyleNe

TES – Thermal Emission Spectrometer (on Mars Observer) [Space]

TFP – Tops Filing Protocol

TFS – Translucent File System

TFT – The Fantasy Trip

TFT – Thin Film Transistor

TG – Thieves’ Guild

TGV – Tres Grande Vitesse (French, Very High Speed) [Railroading]

TGV – Two Guys and a VAX (humorous variant) [Corporate name]

THIEF – THief Isn’t Even Fine

THIEF – This Here Isn’t Even Fine

THOR – Tandy High-intensity Optical Recording

TI – Texas Instruments

TIA – Thanks In Advance [Net jargon]

TIA – Transient Ischemic Attack

TIC – TermInfo Compiler

TID – Ter In Die (three times a day)

TID – Transaction ID

TIFF – Tag Image File Format

TIP – Terminal Interface Processor [ARPANET/MILNET] (replaced by TAC)

TIS – Trusted Information Systems [Corporate name]

TISN – Tokyo International Science Network (Japan)

TKO – Technical Knock Out [Boxing]

TL – Total Loss

TLA – Three Letter Acronym

TLC – Tender Loving Care

TLI – Transort-Level Interface

TM – TradeMark

TMA – Tycho Magnetic Anomaly (movie 2001)

TMAC – Treasury department’s Multiuser Acquisition Contract

TMIS – Telecommunications Management Information System

TMO – Telephone Money Order

TMP – The Morrow Project

TMRC – Tech Model Railroad Club [MIT]

TMRC – Transportation Modeling Research Center (TMRC {above} alter ego)

TN – Tennessee

TN – Twisted Nematic

TNC – Threaded Neill Concelman (connector) [Electronics] (see also BNC)

TNF – Tumor Necrosis Factor [Biology, Medicine]

TNP – Tech Nickel Plate (RR) [TMRC]

TNT – TriNitro Toluene

TO – Telegraph Office

TO – Turn Over

TODS – Transactions on Database Systems (ACM)

TOMS – Total Ozone Mapping Spectrometer [Space]

TOMS – Transactions on Mathematical Software (ACM)

TOOIS – Transactions on Office Information Systems (ACM)

TOP – Technical Office Protocol

TOPLAS – Transactions on Programming Languages and Systems (ACM)

TOPS – Traffic Operator Position System [Telephony]

TOPSMP – Traffic Operator Position System Multipurpose [Telephony]

TORES – Text ORiented Editing System

TOS – Transfer Orbit Stage [Space]

TOW – Tube launched, Optically tracked, and Wire guided

TOY – Time Of Year (clock)

TP – Transaction Processing

TP – Transport Protocol (ISO/CCITT Transport Services (TP0-TP4); like TCP)

TP4 – Transport Protocol, class 4 [ISO]

TPC – The Phone Company (from classic movie: _The President’s Analyst_)

TPI – Tracks Per Inch

TPO – Traveling Post Office

TPP – TetraarylPorPhyrin

TPS – Technical Publishing Software

TPS – TeleProcessing Services

TPS – Thermal Protection System [Space]

TR – Tech Report (at least at LCS (q.v.), maybe others)

TR – Technical Reference [Bell, Telephony]

TRG – Tip and Ring Ground (test) [Telephony]

TROFF – Text RunOFF, text formatter

TRUSIX – TRUSted unIX

TRW – Thompson, Ramo, and Woolridge

TS – Top Secret

TSAP – Transport Service Access Point [OSI, Networking]

TSD – Total System Design

TSP – Teleprocessing Services Program

TSP – Thrift Savings Plan

TSP – Time Synchronization Protocol

TSP – TriSodium Phosphate

TSR – TSR (Fortune 500 Company that manufactures Dungeons & Dragons)

TSS – Tethered Satellite System [Space]

TSTO – Two Stage to Orbit [Space]

T&T – Tunnels & Trolls

TTFN – Tah Tah, For Now

TTL – Transistor Transistor Logic

TTMA – Tennessee Tech Microcomputer Association

TTU – Tennessee Technological University

TTY – TeleTYpe

TUNIS – Toronto UNIversity System

TV – TeleVision

TVA – Tennessee Valley Authority

TW – Thieves’ World

TWA – Trans World Airlines [Corporate name]

TWB – Terrestrial WideBand [Networking, DARPA]

TWIMC – To Whom It May Concern

TWT – Traveling Wave Tube

TWX – TeletypeWriter eXchange

TX – Texas

Tx – Transmit

u – (representing the greek mu) – micro

U – Universe

UA – United Artists

UAR – United Arab Republic

UAR – User Action Routine

UARS – Upper Atmosphere Research Satellite [Space]

UART – Universal Asynchronous Receiver Transmitter

UBA – UniBus Adapter [DEC]

UBC – Universal Bibliographic Control

UBC – University of British Columbia

UBM – Unpressurized Berthing Mechanism [Space]

UCAR – University Corporation for Atmospheric Research

UCB – University of California at Berkeley

UCD – Uniform Call Distributor [Telephony]

UCD – University of California at Davis

UCI – University of California at Irvine

UCL – University College London

UCLA – University of California at Los Angeles

UCR – University of California at Riverside

UCSB – University of California at Santa Barbara

UCSC – University of California at Santa Cruz

UCSD – University of California at San Diego

UCSF – University of California at San Francisco

UDB – Unified DataBase

UDMH – Unsymmetrical DiMethyl Hydrazine [Space]

UDP – User Datagram Protocol

UEC – User Environment Component

UFO – Unidentified Flying Object [Space]

UGC – Uppsala General Catalog [Space]

UH – Upper Half

UHF – Ultra High Frequency (300-3000MHz)

UID – Unique IDentifier

UID – User IDentification [UNIX]

UIMS – User Interface Management System

UIT – Ultraviolet Imaging Telescope (Astro package) [Space]

UIUC – University of Illinois at Urbana-Champaign

UK – United Kingdom

UKST – United Kingdom Schmidt Telescope [Space]

UL – Underwriters Laboratory

ULANA – Unified Local-Area Network Architecture

UMOC – Ugliest Man On Campus [MIT]

UMT – Universal Military Training

UN – United Nations

UNESCO – United Nations Educational, Scientific, & Cultural Organization

UNICEF – United Nations International Children’s Emergency Fund (now United Nat. Child. Fund)

UNICS – UNiplex Information Computer Services

UNIX – Not an acronym at all. – Was a joke on MIT’s MULTICS.

UNMA – Unified Network Management Architecture [AT&T]

UNO – United Nations Organization

UP – Union Pacific [Railroading, Corporate name]

UPC – Universal Product Code

UPI – United Press International

UPI – United Press International [Corporate name]

UPS – Uninterruptible Power Supply

UPS – United Parcel Service [Corporate name]

UR – University of Rochester

URI – University of Rhode Island

US – United States (of America)

USA – Union of South Africa

USA – United States Army

USA – United States of America

USAF – United States Air Force

USAFA – United States Air Force Academy (in Colorado Springs)

USAN – University Satellite Network

USB – Upper Side Band

USC – University of Southern California

USCG – United States Coast Guard

USDA – United States Department of Agriculture

USES – United States Employment Service

USFL – United States Football League

USGS – United States Geological Survey

USIA – United States Information Agency

USM – United States Mail

USMC – United States Marine Corps

USMP – United States Microgravity Payload [Space]

USN – United States Navy

USO – United Service Organizations

USO – Unix Software Operation

USP – United States Pharmacopeia

USPS – United States Postal Service

USR – User Service Routines

USS – United States Ship

USSR – Union of Soviet Socialist Republics

USSS – User Services and Systems Support

USW – Und So Weiter

UT – Universal Time (a.k.a. GMT, UTC, or Zulu Time)

UT – University of Tennessee

UT – University of Texas

UT – UTah

UTC – Coordinated Universal Time (a.k.a. UT)

UTC – Universal Coordinated Time (a.k.a. UT)

UTnet – University of Texas Network

UTP – Unshielded Twisted Pair [Telecom, Networking]

UUCP – UNIX-to-UNIX Copy Program

UUG – Unix User Group

UV – UltraViolet

UVS – UltraViolet Spectrometer

UW – UnderWriter

UW – Univ of Wisconsin

VA – Veterans Administration

VA – Virginia

VAB – Vehicle Assembly Building (formerly Vertical Assembly Building) [Space]

VAFB – Vandenberg Air Force Base [Space]

VAN – Value Added Network (e.g. Tymnet, Telenet, etc)

VANS – Value-Added Network Services

VAR – Value Added Remarketer (reseller)

VASI – Visual Approach Slope Indicator

VAT – Value Added Tax

VAX – Virtual Address eXtended

VAXBI – VAX Bus Interconnect

VC – Viet Cong

VC – Virtual Circuit

Vcc – Voltage (Common Cathode?)

VCM – Voice Coil Motor

VCO – Voltage Controlled Oscillator

VCR – VideoCassette Recorder

VCU – Virginia Commonwealth University

VD – Venereal Disease (see also STD)

VDFM – Virtual Disk File Manager

VDI – Virtual Device Interface

VDM – Vienna Development Method

VDM – Virtual Device Metafile

VDT – Video Display Terminal

VEEGA – Venus-Earth-Earth Gravity Assist (Galileo flight path) [Space]

VF – Video Frequency

VF – Voice Frequency

VFO – Variable Frequency Oscillator

VFR – Visual Flight Rules [Aviation]

VFW – Veterans of Foreign Wars

VFW – Volunteer Fire Department

VG – Very Good

VG – Vicar-General

VGA – Video Graphics Array

Vgg – Voltage (Gate to Ground?)

V&H – Vertical and Horizontal (CO coordinate tape) [Telephony]

VHDL – Vhsic Hardware Description Language

VHF – Very High Frequency (30-300MHz)

VHS – Video Home System (VCR)

VHSIC – Very High Speed Integrated Circuit

VI – VIsual editor

VIABLE – Vertical Installation Automation BaseLinE

VILE – VI Like Emacs

VINE – Vine Is Not Emacs

VIP – Very Important Person

VISTA – Volunteers In Service To America

VITA – Vme International Trade Association

VJ – Video Jockey

VL – Vulgar Latin

VLA – Very Large Array [Space]

VLBA – Very Long Baseline Array [Space]

VLBI – Very Long Baseline Interferometry [Space]

VLF – Very Low Frequency (3-30KHz)

VLIW – Very Long Instruction Word

VLSI – Very Large Scale Integration

VLT – Very Large Telescope [Space]

VM – Virtual Memory

VM/CMS – Virtual Machine/Conversational Monitor System

VMM – Virtual Memory Manager

VMOS – Vertical Metal Oxide Semiconductor (V-MOS) (see MOS)

VMR – Vertical Market Reseller

VMS – Vertical Motion Simulator [Space]

VMS – Virtual Memory System [DEC]

VOA – Voice Of America

VOIR – Venus Orbiting Imaging Radar (superseded by VRM) [Space]

VOIS – Voice-Operated Information System

VOQ – Visiting Officer’s Quarters

VPI&SU – Virginia Polytechnic Institute and State University

VRC – Vertical Redundancy Character

VRM – Venus Radar Mapper (now called Magellan) [Space]

VRM – Virtual Resource Manager

VSAT – Very Small Aperture Terminal (satellite dish)

VSX – X/open Verification Suite

VTAM – Virtual Telecommunications Access Method [IBM]

VTOC – Volume Table Of Contents

VTOL – Vertical TakeOff and Landing

VTR – VideoTape Recorder

VUP – Vax Unit of Performance

V&V – Villains & Vigilantes

VVSS – Vertical Volute Spring Suspension

W – West

W – Width

WA – Washington

WA – Western Australia

WAC – Womens Air Corps

WAIS – Wide Area Information Server

WARC – World Administrative Conference

WATS – Wide Area Telephone Service

WB – Water Ballast

WB – WayBill

WBC – White Blood Cells

WC – Water Closet

WC – Without Charge

WCTU – Women’s Christian Temperance Union

WD – White Dwarf [Space]

w.d. – will dated [Genealogy]

WECo – Western Electric Company [AT&T] (manufacturing arm of AT&T)

WFPC – Wide Field / Planetary Camera (on HST) [Space]

WFPCII – Replacement for WFPC [Space]

WG – Working Group

WH – WarHammer

WHBL – World Home Bible League

WHCA – White House Communications Agency [US Government]

WHO – World Health Organization

WI – Wisconsin

WIMP – Windows/Icons/Mouse Programming(?)

WIPP – (nuclear) Waste Isolation Pilot Plant [DOE]

WIS – WWMCCS Information System

WITS – Washington Interagency Telecommunications System

WIYN – Wisconsin / Indiana / Yale / NOAO telescope [Space]

WMSCR – Weather Message Switching Center Replacement

WOM – Write Only Memory

WOP – WithOut Papers [Immigration]

WOPR – War Operations Planned Response (from “Wargames” movie)

WORM – Write Once, Read Many times

WOW – Worlds of Wonder

w.p. – will proved [Genealogy]

WP – Word Processing

WP – Working Paper

WPI – Worcester Polytechnic Institute

WSI – Wafer Scale Integration

WSMR – White Sands Missile Range [Space]

WSW – West-SouthWest

WTR – Western Test Range [Space]

WU – Washington University

WU – Western Union

WUPPE – Wisconsin Ultraviolet PhotoPolarimter Experiment (Astro package) [Space]

WV – West Virginia

WW – World War

WWI – World War I

WWII – World War II

WWMCCS – World-Wide Military Command and Control System

WY – Wyoming

WYSIWIS – What You See Is What I See

WYSIWYG – What You See Is What You Get

XCF – eXperimental Computing Facility

XD – without Dividend

XDR – eXternal Data Representation

XFER – Transfer

XINU – XINU Is Not UNIX

XL – eXtra Large

XMM – X-ray Multi Mirror [Space]

XMTR – transMiTteR (the X is for trans)

XNS – Xerox Network Services

XO – eXecutive Officer

XOR – eXclusive OR (logical function)

XPORT – Transport

XSECT – cross SECTion

XTAL – crysTAL (another version of x for crys, see XMTR)

XUI – X-windows User Interface

XUV – eXtreme UltraViolet [Space]

YA – Yet Another

YACC – Yet Another Compiler Compiler

YB – YearBook

YMCA – Young Mens Christian Association

YMHA – Young Mens Hebrew Association

YOB – Year Of Birth

YP – Yellow Pages

YRS – Ysgarth Rules System

YSO – Young Stellar Object [Space]

YST – Yukon Standard Time

YT – Yukon Territory

YT – Yukon Time

YTD – Year To Date

YWCA – Young Womens Christian Association

YWHA – Young Womens Hebrew Association

Z – Zenith

Z – Zero

Z – Zulu (time)

ZB – Zero Beat

ZETA – Zero Energy Thermonuclear Assembly

ZGS – Zero Gradient Synchrotron

ZI – Zonal Index

ZIF – Zero Insertion Force (connector/socket)

ZIP – Zone Improvement Plan (US post office code)

ZK – barrage balloon (navy symbol)

ZMRI – Zinc Metals Research Institute

ZPG – Zero Population Growth

ZPRSN – Zurich Provisional Relative Sunspot Number

ZST – Zone Standard Time

ZT – Zone Time

ZWEI – Zwei Was Eine Initially