2D	2-Dimensional

3ACC	3A Central Control

3D	3-Dimensional

3M	Minnesota Mining and Manufacturing

4GL	Fourth Generation Language

4H	Head, Heart, Hands, Health

5XBCOER	5 X-Bar Central Office Equipment Reports system, "5XB COER"

AAAAAA	Association for the Abolition of Abused Abbreviations and Asinine Acronyms

AAA	American Automobile Association

AAA	Anti-Aircraft Artillery

AA	Administrative Assistant

AA	Affirmative Action committee

AAAL	American Academy of Arts and Letters

AA	Alcoholics Anonymous

AA	American Airlines

AA	Antiaircraft Artillery

AAAS	American Association for the Advancement of Science

AA	Associate in Accounting

AA	Astronomy and Astrophysics, "A&A"

AA	Automobile Association (in England)

A	Aftermath

AAII	American Association of Individual Investors

AAMOF	As A Matter Of Fact

AAMSI	American Association for Medical Systems Informatics

AAO	Anglo-Australian Observatory

AAP	Affirmative Action Program

AARC	Anglo-American Cataloging Rules

AARP	Appletalk ARP

AAS	American Astronomical Society

AAS	Atom Absorption Spectrometry

AAVSO	American Association of Variable Star Observers

AAX	Automated Attendant eXchange

ABA	American Bar Association

ABA	American Basketball Association

ABA	American Booksellers Association

AB	Able Bodied seaman

ABATS	Automatic Bit Access Test System

ABBR	ABBReviation

ABC	American Broadcasting Company

ABEL	Advanced Boolean Expression Language (a Data-I/O Trademark)

ABHC	Average Busy Hour Calls

ABI	American Bell Inc

ABI	Application Binary Interface (SunOS and SV application sw interface std)

ABM	Asynchronous Balanced Mode

ABP	Alt.Binary.Pictures

ABPE*	Alt.Binaries.Pictures.Erotica.* (.bondage, .leather, etc.)

ABS	Acrylonitrile Butadiene-Styrene (plastic)

ABS	Alternative Billing Service

ABS	American Bureau of Shipping

ABS	Anti-Blocking System

ABSBH	Average Busy Season Busy Hour

ACAA	Agricultural Conservation and Adjustment Administration

AC	Access Control

AC	Adaptive Control

AC	Alternating Current (ac, see also DC)

AC	Answer Center (Sun)

AC	Ante Christum (before Christ)

AC	Ante Cibum (before meals)

ACAWS	Advisory, Caution, And Warning System

ACB	Annoyance Call Bureau

ACBL	American Contract Bridge League

ACC	Argonne Code Center

ACC	Audio Communications Controller

ACCRA	American Chamber of Commerce Research Association

ACCS	Army Command and Control System

ACCS	Automated Calling Card Service

ACCT	Account

ACDA	Automatic Call Disposition Analyzer

ACD	Automatic Call Distributor [telephony]

ACE	Advanced Composition Explorer

ACE	Advanced Computing Environments [Corporate name]

ACE	Automatic Calibration and Equalization

ACE	Automatic Calling Equipment

ACF	Advanced Communications Functions

ACH	Attempt per Circuit per Hour

ACHEFT	Automated ClearingHouse Electronic Funds Transfer

ACIA	Asynchronous Communications Interface Adapter

ACK	ACKnowledge

ACK	Amsterdam Compiler Kit

ACL	Access Control List

ACL	Advanced Cmos Logic

ACLU	American Civil Liberties Union

ACM	Access Control Machine

ACM	Association for Computing Machinery

ACO	Acronym Control Officer

ACOF	Attendant Control Of Facilities

ACP	ACtion Point

ACRNEMA	a medical imaging standard, "ACR/NEMA"

ACRV	Assured Crew Return Vehicle (or) Astronaut Crew Rescue Vehicle

ACS	Advanced Communications System

ACS	Australian Computer Science

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

ACSNET	Acedemic Computing Services NETwork

ACSU	Advanced t-1 Channel Service Unit

ACTPU	ACTivate Physical Unit (SNA)

ACTS	Advanced Communications Technology Satellite

ACTS	Automated Coin Toll Service

ACTS	Automatic Coin Telephone Service  [telephony]

ACTUP	AIDS Coalition To Unleash Power, "ACT UP"

ACU	Alarm Control Unit

ACU	Automatic Calling Unit

ACW	Alternating Continuous Waves

ACWP	Actual Cost of Work Performed

ADA	Air Defense Artillery

ADA	Alternate Delay Accumulation

AD	Addendum

AD	After Date

AD	Analog to Digital converter, "A/D" (see ADC)

AD	Anno Domini (in the year of our Lord)

AD	Application Development

ADB	A DeBugger

ADB	Apple Desktop Bus

ADC	Analog to Digital Converter

ADCCP	Advanced Data Communications Control Procedure

ADCI	Automatic Display Call Indicator

ADD	Advanced Dungeons & Dragons, "AD&D"

ADDCP	Advanced Data Communication Control Procedure

ADEW	Andrew Development Environment Workbench

ADF	Automatic Direction Finder

ADFRF	Ames-Dryden Flight Research Facility (was DFRF) (NASA)

AD(H)D	Attention Deficit (Hyperactivity) Disorder

ADI	Acceptable Daily Input

ADI	Anolog Device Inc

ADM	Additional Dealer Markup

ADM	ADMiral

ADM	Advanced Micro Devices

ADMD	Administration Management Domain

ADN	Abbreviated Dialing Number

ADP	Adenosine Di-Phosphate

ADP	Administrative Data Processing

ADP	Advanced Data Processing

ADP	Automatic Data Processing

ADPCM	Pulse Code Modulation with Adaptive Quantization

ADSL	Asymmetric Digital Subscriber Line

ADS	Advanced Digital System

ADS	Application Development System

ADS	Audio Distribution System

ADS	Automatic Voice System

ADS	Auxilary Data System

ADSP	AppleTalk Data Stream Protocol

ADSR	Attack Decay Sustain Release

ADT	Abstract Data Type

ADT	Atlantic Daylight Time

AEA	American Electronics Association

AEA	Atomic Energy Authority

AE	Application Entity/Environment/Execution/Engineering (APE)

AEC	Architectural Engineering Construction

AEC	Atomic Energy Commission

AEF	American Expeditionary Force (see BEF)

AEGIS	Advanced Electronic Guidance and Instrumentation System

AES	Application Environment Specification

AFACTS	Automatic FACilities Test System

AF	Address Family (sockets)

AFADS	Automatic Force Adjustment Data System

AF	Adventures in Fantasy

AFAICR	As Far As I Can Recall

AFAICT	As Far As I Can Tell

AFAIK	As Far As I Know

AFAIR	As Far As I Recall

AF	Air Force

AFATDS	Advanced Field Artillery Tactical Data System

AF	Audio Frequency

AFB	Air Force Base

AFCAC	Air Force Computer Acquisition Center

AFC	American Football Conference

AFC	Automatic Frequency/Flight Control

AFCC	Air Force Communications Command

AFGE	American Federation of Government Employees

AFI	Authority and Format Identifier

AFIPS	American Federation of Information Processing Societies

AFK	Away From Keyboard

AFL	American Federation of Labor

AFL	American Football League

AFLCIO	American Federation of Labor; Congress of Industrial Organizations, "AFL-CIO"

AFM	Adobe Font Metrics

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

AFSK	Automatic Frequency Shift Keying

AFTRA	American Federation of Television and Radio Artists

AFUU	Association Francaise des Utilisateurs d'Unix

AG	Adjutant General

AG	Arcade Game

AG	Attorney General

AGCT	Army General Classification Test

AGL	Above Ground Level

AGM	Air-to-Ground Missile

AGN	Active Galactic Nucleus

AGU	American Geophysical Union

AHA	American Homebrew Association

AH	Artificial Horizon

AH	Avalon Hill (major war game manufacturer)

AHL	American Hockey League

AHQ	Air HeadQuarters

AIAA	American Institute of Aeronautics and Astronautics

AIA	American Institute of Architects

AIA	Application Integration Architecture

AI	Allegheny International

AI	Amnesty International

AI	Anal Intrusion

AI	Artificial Insemination

AI	Artificial Intelligence

AI	Attitude Indicator

AIC	Automatic Intercept Center

AICC	Automatic Intercept Communications Controller

AID	Agency for International Development

AIDDE	Ames' Interactive Dynamic Display Editor

AIDS	Acquired ImmunoDeficiency Syndrome

AIM	Air Interception Missile

AIM	Airman's Information Manual

AIMS	Advanced Inventory Management System

AIOD	Automatic Identification Outward Dialing 

AIPS	Astronomical Image Processing System

AIS	Action Item System

AIS	Automatic Intercept System

AIUI	As I Understand It

AIX	Advanced Interactive eXecutive (unix)

AJ	Astronomical Journal

AKA	Also Known As

AK	Alaska

ALA	American Library Association

ALA	Automobile Legal Association

AL	Alabama

AL	American League (baseball)

ALAP	AppleTalk-LocalTalk Link Access Protocol

ALBM	Air-to-Land Ballistic Missile

ALBO	Automatic Line BuildOut

ALC	Automatic Load Control

ALEXIS	Array of Low Energy X-ray Imaging Sensors

ALFA	Anonima Lombarda Fabbrica Automobili

ALFE	Analog Line Front End

ALGOL	ALGorithmic Oriented Language

ALI	Automatic Location Indentification

ALIT	Automatic Line Insulation Testing

ALM	Asychronous Line Module

ALM	Asynchronous Line Multiplexer

ALMS	alt.lifestyle.master.slave

ALPO	Association of Lunar and Planetary Observers

ALRU	Automatic Line Record Update

ALS	Advanced Launch System [Space]

ALS	Automated List Service

ALU	Arithmetic Logic Unit

AMA	American Medical Association

AMA	Association for Model Aviation

AMA	Automatic Message Accounting

AMACS	Automatic Message Accounting Collection System

AM	Administrative Module

AM	Agricultural and Mechanical, "A&M"

AM	Air Marshal

AM	Alpes-Maritimes, "A.-M."

AM	American, "Am."

AM	Americium, "Am"

AM	Amplitude Modulation

AM	anno mundi (in the year of the world)

AM	Ante Meridiem, "a.m." (before noon)

AMARC	Automatic Message Accounting Recording Center

AMASE	Automatic Message Accounting Standard Entry

AMAT	Automatic Message Accounting Transmitter

AMATPS	Automatic Message Accounting TeleProcessing System

AMBA	Association of Master of Business Administration

AMC	Albany Medical College

AMD	Advanced Micro Devices [Corporate name]

AMERITECH	AMERican Information TECHnologies

AMEX	AMerican EXpress

AMI	American Micro System Inc

AMORC	Ancient Mystic Order Rosae Crucis

AMP	Adenosine MonoPhosphate

AMPAS	Academy of Motion Picture Arts and Sciences

AMPS	Advanced Mobile Phone Service

AMRAAM	Advanced Medium Range Air-To-Air Missile

AMROC	American Rocket Company [Space]

AMSAT	radio AMateur SATellite corp.

AMT	Active Memory Technology

AMU	Atomic Mass Unit

AMVET	AMerican VETeran

ANA	American Nurses Association

ANA	Automatic Number Announcement

ANAC	Automatic Number Announcement Circuit [telephony]

AN	Associated Number

ANC	All Number Calling [telephony]

ANC	American Network Communications

ANC	Army Nurse Corps

ANDF	Architecture-Neutral Distribution Format

ANF	Automatic Number Forwarding 

ANFSCD	And Now For Something Completely Different

ANG	Air National Guard

ANI	Automatic Number Identification [telephony]

ANIF	Automatic Number Identification Failure

ANL	Argonne National Laboratory

ANOVA	ANalysis Of VAriance

ANPA	American Newspaper Publishers Association

ANSI	American National Standards Institute

ANU	Australian National University

ANZUS	Australia, New Zealand, United States

AOA	Abort Once Around (Shuttle abort plan)

AO	Account Of

AOCS	Attitude and Orbit Control System

AOL	Absent Over Leave (see AWOL)

AOPA	Aircraft Owners and Pilots Association

AOP	Annual Operating Plan

AOQ	Average Outgoing Quality

AOS	Academic Operating System

AOS	Alternate Operator Service [telephony]

AOSS	Auxilliary Operator Service System

AOW	Asia and Oceania Workshop

APA	All Points Addressable

AP	Access Point

AP	Accounts Payable, "A/P"

AP	Additional Premium

AP	Age Play

AP	All Points

AP	Application Process

AP	Associated Press

AP	Attached Processor

APB	All Points Bulletin

APC	AMARC Protocol Converter

APDA	Apple Programmers and Developers Association

APDU	Application Protocol Data Unit

APE	APplication Engineering

APG	Aberdeen Proving Ground

API	American Petroleum Institute

API	Application Program(ming) Interface

APICS	American Production and Inventory Control Society

APJ	Astrophysical Journal, "Ap.J", "ApJ"

APL	A Programming Language

APM	Attached Pressurized Module (a.k.a. Columbus)

APO	Alpha Pi (?) Omega, service fraternity

APO	Army Post Office

APP	Application Portability Profile

APPC	Advanced Peer-to-Peer Communications

APPC	Advanced Program-to-Program Communication (IBM)

APR	Annual Percentage Rate

APS	Automatic Protection Switch

APSE	Ada Programming Support Environment

APT	Attached Proton Test

APU	Auxiliary Power Unit

AQ	Accumulator-Quotient register

AQL	Acceptable Quality Level

AR	Accounts Receivable, "A/R"

AR	Address Register

AR	Alarm Report

ARAMIS	American Rheumatic Arthritis Medical Information System

AR	Arkansas

ARC	Advanced RISC Computing

ARC	American Red Cross

ARC	Ames Research Center (NASA)

ARC	Audio Response Controller

ARCNET	Attached Resource Computer local area NETwork

ARCO	Atlantic Richfield COmpany

ARIS	Audichron Recorded Information System

ARLL	Advanced Run-Length Limited encoding

ARM	Acorn Risc Machine

ARM	Adjustable Rate Mortgage

ARM	Annotated Reference Manual

ARO	After Receipt of Order

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

ARP	Address Resolution Protocol (Internet->Ethernet)

ARPANET	Advanced Research Projects Agency NETwork

ARQ	Automatic Repeat reQuest

ARRL	Amateur Radio Relay League

ARSA	Airport Radar Service Area

ARS	Alternate Route Selection

ARSB	Automated Repair Service Bureau

ARTCC	Air Route Traffic Control Center

ARTEMIS	Advanced Relay TEchnology MISsion

ARU	Audio Response Unit

ARV	American Revised Version

ASA	Acetyl Salicylic Acid

ASA	American Standards Association (now ANSI)

ASA	Astronomical Society of the Atlantic

ASAIGAC	As Soon As I Get A Chance

AS	Anglo-Saxon

ASAP	As Soon As Possible

ASB	Alt.Sex.Bondage

ASC	Accredited Standards Committee

ASC	Additional Sense Code

ASCAP	American Society of Composers, Authors, and Publishers

ASCC	Automatic Sequence-Controlled Calculator

ASCII	American Standard Code for Information Interchange

ASCQ	Additional Sense Code Qualifier

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

ASDSP	Application-Specific Digital Signal Processor

ASF*	alt.sex.fetish.*

ASFD	alt.sex.femdom/ alt.sex.fetish.diapers

ASG	Automated Sciences Group

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

ASI	Agenzia Spaziale Italiano

ASI	Asynchronous SCSI Interface

ASI	Automatic System Installation

ASIC	Application Specific Integrated Circuit

ASIS	Aromatic Solvent Induced Shift

ASK	Akademische Software Kooperation

ASK	Amplitude Shift Keying

ASL	(a/s/l) Age, Sex, Location (usually impolite IRC query)

ASM	American Society of Metals

ASME	American Society of Mechanical Engineers

ASN1	Abstract Syntax Notation One, "ASN.1"

ASN	Abstract Syntax Notation

ASOC	Administrative Service Oversight Center

ASP	Aggregated Switch Procurement

ASP	Appletalk Session Protocol

ASPEN	Automatic System for Performance Evaluation of the Network

ASR	Airport Surveillance Radar

ASRM	Advanced Solid Rocket Motor

ASRS	Aviation Safety Reporting System

ASS	Alt.Sex.Spanking/Stories, depending on context

ASSR	Autonomous Soviet Socialist Republic

AST	Applied System Technology

AST	Asyncronous System Trap

AST	Atlantic Standard Time

ASTM	American Society of Testing and Materials

ASV	American Standard Version

ATA	Airport Traffic Area

ATA	AT Attachment

ATA	Automatic Trouble Analysis

ATACC	Advanced Tactical Air Command Central

AT	Access Tandem

AT	Advanced Technology

AT	Atlantic Time

ATB	Advanced Technology Bomber (stealth bomber)

ATB	All Trunks Busy

ATB	Alt.Talk.Bestiality

ATC	Air Traffic Control

ATC	Atsugi Technical Center

ATC	Automatic Transmission Control

ATDRS	Advanced Tracking and Data Relay Satellite

ATE	Automatic Test Equipment

ATEOTD	At The End of the Day

ATF	Advanced Technology Fighter

ATH	Abbreviated Trouble History

ATI	Automatic Test Inhibit

ATIS	Atherton Tools Interface Specification

ATIS	Automatic Terminal Information Service

ATIS	Automatic Transmitter Identification System

ATK	Andrew ToolKit

ATLAS	Atmospheric Laboratory for Applications and Science

ATM	Adobe Type Manager

ATM	Amateur Telescope Maker

ATM	Asynchronous Transfer Mode

ATM	Asynchronous Transfer Mode

ATM	At The Moment

ATM	Automatic Teller Machine

ATMS	Automated Trunk Measurement System

ATN	Automated Test Network

ATO	Abort To Orbit (Shuttle abort plan)

ATOMS	AT&t Optimized Materials Simulator

ATP2	AppleTalk Phase 2

ATP	Adenosine TriPhosphate

ATP	Airline Transport Pilot (highest grade of pilot certificate)

ATP	All Tests Pass

ATP	Appletalk Transaction Protocol

ATPCO	Airline Tariff Publishing COmpany

ATR	Alternate Trunk Routing

ATR	Apollo Token Ring

ATRS	Automated Trouble Reporting System

ATS	Automated Test System

ATSL	Along The Same Line

ATT	American Telephone & Telegraph, "AT&T"

ATTC	Automatic Transmission Test and Control circuit

ATTCOM	American Telephone & Telegraph COMmunications

ATTIS	American Telephone & Telegraph Information Systems

ATV	All Terrain Vehicle

AU	Arithematic Unit

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

AUDIX	AUDio Information eXchange

AUI	Attachment Unit Interface

AUP	Acceptable Use Policy

AUP	Acceptable Use Policy

AURA	Association of Universities for Research in Astronomy

AUS	Army of the United States

AUTODIN	AUTOmatic DIgital Network

AUTOSEVCOM	AUTOmatic SEcure Voice COMmunications

AUTOVON	AUTOmatic VOice Network

AUX	Apple UniX

AUXF	AUXillary Frame

AV	AudioVisual

AVD	Alternate Voice Data

AVLIS	Atomic Vapor Laser Isotope Separation

AVS	Application Visualization Software

AWACS	Airborne Warnings And Control Systems

AWEA	American Wind Energy Association

AWG	American Wire Gauge

AWGTHTGTTA	Are We Going To Have To Go Through This Again

AWHFY	Are We Having Fun Yet

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

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

AWST	Aviation Week and Space Technology (a.k.a. AvLeak), "AW&ST"

AXAF	Advanced X-ray Astrophysics Facility [Space]

AY	Arther Young

AZ	Arizona

B4	Before

B4N	Bye For Now

B6ZS	Bipolar with 6 Zero Subsitution

B911	Basic 911

BA	Bachelor of Arts

BAC	By Any Chance

BACH	Business Alliance for Commerce in Hemp

BAFO	Best And Final Offer

BAG(L)	Busting A Gut (Laughing)

BALUN	BALanced to UNbalanced

BAMAF	BELLCORE AMA Format

BANCS	Bell Administrative Network Communications System

BAPCO	Bellsouth Advertising & Publishing COmpany

BARRNET	Bay Area Regional Research Network, "BARRNet" (SF Bay Area)

BASH	Bourne-Again SHell

BASIC	Beginner's All-purpose Symbolic Instruction Code

BATSE	Burst And Transient Source Experiment (on GRO)

BBA	Bachelor of Business Administration

BB	Bases on Balls

BBB	Better Business Bureau

BB	Best of Breed

BB	Bunnies and Burrows

BBC	British Broadcasting Corporation

B	bit, "b"

BBIAB	Be Back In A Bit

BBL	Barrel

BBL	[I'll] Be Back Later

BBM	Big Beautiful Man

BBN	Bolt, Beranek, and Newman [Corporate name]

B	Book

BBW	Big Beautiful Woman