This is a list of initialisms, acronyms that are pronounced as a series of the names of the constituent letters (but, there is disagreement on some; e.g. RBOC as "are-bock").
A,B,C
- AA - Alcoholics Anonymous - Automobile Association
- AAA - formerly American Automobile Association; now officially known by the initials; often pronounced "Triple A"
- AAD - analogue analogue digital - Australian Antarctic Division
- AARP - formerly American Association of Retired Persons, but now officially known only by the initials
- AAS - American Astronomical Society; pronounce "Double A S"
- ABA - American Bar Association / American Basketball Association
- ABC - alcoholic-beverage commission - alien big cat - Always Be Careful - American-Born Chinese - American Broadcasting Company - anti-lock brake controller - Associated British Corporation - Atanasoff Berry Computer - Atlantic Baptist College - Atomic Biological Chemical (see NBC) - Australian Broadcasting Corporation
- ABM - anti-ballistic missile - Asynchronous Balanced Mode - automated banking machine
- ABN - Australian Business Number - a number issued by the Australian government as registration of a business. Used for taxation purposes
- ABS - acrylonitrile butadiene styrene - anti-lock braking system
- AC - adriamycin-cyclophosphamide (chemotherapy) - alternating current - Anonymous Coward - ante christum - air conditioning - Albert Champion - Associazione Calcio (Italian for "football (soccer) club")
- ACC - Automatic Climate Control / Atlantic Coast Conference
- ACF - American Culinary Federation
- ACN - Australian Company Number - a number issued by the Australian government as registration of a company (limited liability) in Australia.
- ACL - Access Control List / anterior cruciate ligament
- ACLU - American Civil Liberties Union
- ACM - see entry
- ACS - American Chemical Society, American Cancer Society, Association of Caribbean States
- AD - Latin "Anno Domini" (In the year of our Lord)
- ADA - American Dental Association
- ADD - analogue digital digital - attention-deficit disorder
- ADHD - Attention-Deficit Hyperactivity Disorder
- ADHS - attention-deficit hyperactivity syndrome
- ADL - Anti-Defamation League
- ADM - Archer Daniels Midland
- ADS - attention-deficit syndrome
- ADT - Atlantic Daylight Time (UTC-3 hours)
- AFACT - As far as I can tell
- AFAIC - As far as I'm concerned
- AFAIK - As far as I know
- AFAIR - As far as I remember/recall
- AFJ - April Fool's Joke
- AFK - Away from keyboard
- AFL - American Federation of Labor - American Football League - Arena Football League - Australian Football League
- AGA - Advanced Graphics Architecture
- AGM - Annual General Meeting
- AI - Amnesty International; Artificial Intelligence
- AIA - Aerospace Industry Association
- AIC - African Independent Church
- AIDS - Acquired Immunodeficiency Syndrome
- AIM - AOL Instant Messenger, among others
- AIPAC - American Israel Public Affairs Committee
- aka - also known as
- AKDT - Alaska Standard Daylight Saving Time (UTC-8 hours)
- AKST - Alaska Standard Time (UTC-9 hours)
- ALS - Amyotrophic lateral sclerosis
- AM - see entry
- AMA - American Medical Association
- AMD - Advanced Micro Devices
- AMS - American Mathematical Society
- ANC - African National Congress
- ANSI - American National Standards Institute
- AOL - America Online
- AP - Associated Press / Advanced Placement
- apm - Advanced Power Management
- ASA - Acetesalicylic acid - American Standards Association - Army Security Agency - Atlantic Southeast Airlines
- ASCII - American Standard Code for Information Interchange
- ASDF - Attack, Sustain, Decay, Release (sound envelope specification)
- ASEAN - Association of Southeast Asian Nations
- ASIO - Australian Security Intelligence Service
- ASL - American Sign Language
- ASP - Application service provider
- ASP - Active Server Pages
- AST - Atlantic Standard Time (UTC-4 hours)
- AT&T - American Telephone and Telegraph Company
- ATM - automated teller machine - asynchronous transfer mode
- ATV - All-Terrain Vehicle
- AUC - 1. Latin "AB URBE CONDITA" (from the founding of the city (of Rome) or "ANNO URBIS CONDITAE" (in the year from the founding of the city (of Rome) 2. "area under the curve" in the concentration time curve (medicine)
- AVO - Apprehended Violence Order
- B&W - black and white - Babcock & Wilcox
- B2B - Business to Business
- B2C - Business to Customer
- B2E - Business to Employee
- BART - Bay Area Rapid Transit
- BASF - Badische Anilin und Soda Fabrik
- BATF - Bureau of Alcohol, Tobacco, and Firearms
- BB - Brigitte Bardot (actress) / Boys' Brigade (Christian youth organisation)
- BBB - blood-brain barrier - Better Business Bureau
- BBC - British Broadcasting Corporation
- BBQ - Barbeque
- BC - Before Christ / Blind Copy (in emailers) / British Columbia / Boston College
- BCC - Blind Carbon Copy
- BCE - Before Common Era - British Columbia Electric - Banque Centrale Européenne
- BCS - Bowl Championship Series (US college football)
- BDA - British Dental Association
- BDU - battle-dress uniform
- BFE - Beyond/Butt F*****' Egypt (colloquial for "quite far away")
- BJT - bipolar junction transistors
- BMI - Broadcast Music Incorporated / Body mass index
- BMW - Bayerische Motoren Werke/Bavarian motor-works
- BMX - Bicycle Motor Cross
- BNS - Bank of Nova Scotia
- BO2K - Back Orifice 2000
- BOAC - British Overseas Airways Corporation
- BOFH - Bastard operator from hell
- BP - British Petroleum (today, BP doesn't officially stand for everything)
- bpm - Beats per minute
- BRB - Internet chat abbreviation, "be right back"
- BSA - Boy Scouts of America / Birmingham Small Arms Company (motorcycles)
- BSD - Berkeley Software Distribution (distinct from BSoD)
- BSE - Bovine Spongiform Encephalopathy, better known as Mad Cow disease
- BSL - British Sign Language
- BSoD - Blue screen of death (distinct from BSD)
- BST - bovine somatatotrophin hormone - Blended Sales Tax - British Summer Time
- BIOS - Basic Input Output System
- BT - British Telecommunications plc
- BTO - Built to Order
- BTU - British thermal unit
- BTW - By the way
- BWR - boiling-water reactor
- BYOB - Bring your own beverages/bottle
- BYU - Brigham Young University
- CAIR - Council on American-Islamic Relations
- CB - citizens' band radio
- CBC - Canadian Broadcasting Corporation
- CBM - Canadian Baptist Ministries - Commodore Business Machines
- CC - carbon copy
- CCCP - Cyrillic letters corresponding SSSR, see USSR
- CCD - charge-coupled device
- CD - Compact disc
- CDC - Centre for Disease Control and prevention - Control Data Corporation
- CE - Common (or Christian) Era (cf. AD)
- CEO - Chief executive officer
- CEPT - Conference Européenne des administration des Postes et des Télécommunications (European Conference of Postal and Telecommunications Administrations)
- cf. - Latin confer (compare, or see also)
- CFG - Context-free grammar, Control flow graph
- CFSP - Common Foreign and Secruity Policy
- CIA - Central Intelligence Agency - Culinary Institute of America
- CID - Criminal Investigations Department
- CIO - Chief information officer - Congress of Industrial Organisations
- CIS - Commonwealth of Independent States (former Soviet Union) / Canadian Interuniversity Sport
- CJC - Canadian Jewish Congress
- CLEC - Competitive Local Exchange Carrier
- CLI - command line interface/interpreter
- CMHC - Canada Mortgage and Housing Corporation
- CMM - Capability Maturity Model
- CMOS - complementary metal-oxide-semiconductor
- CMR - Coaxial Main Rotors (helicopter type)
- CMYK - cyan magenta yellow key (colour model)
- CND - Campaign for Nuclear Disarmament
- CNN - Cable News Network
- CO - Central Office (Phone Company office or POP)
- COD - cash on delivery
- COLA - cost of living adjustment
- CPA - Certified Practicing Accountant
- CPPCC - Chinese People's Political Consultative Conference
- CPU - central processing unit
- CQD - come quick, distress (?)
- CRC - Christian Reformed Church - Cyclic redundancy check - Chemical Rubber Company
- CRM - Customer Relationship Management
- CRT - cathode ray tube - Chinese remainder theorem
- CRTC - Canadian Radio-television and Telecommunications Commission
- CSA - Confederate States of America - Canadian Standards Association - Canadian Space Agency - Child Support Agency - Czech Airlines - Community Supported Agriculture
- CSI - multiple meanings
- CSICOP - Committee for the Scientific Investigation of Claims of the Paranormal
- CSIS - Canadian Security Intelligence Service - Center For Strategic & International Studies
- CSS - Cascading Style Sheets - content-scrambling system - cross site scripting
- CTSS - Compatible Time-Sharing System
- CUPE - Canadian Union of Public Employees
- CUPW - Canadian Union of Postal Workers
- CV - see entry
- CVR - Cockpit voice recorder
- CWC - Chemical Weapons Convention
D,E,F
- d/b/a - doing business as
- DC - da capo - Italian Democrazia Cristiana - direct current - District of Columbia - Douglas Aircraft Company - Dublin Core - duty cycle
- DDA - digital differential analyzer
- DDD - digital digital digital (CD quality) - Data Display Debugger
- DDR - Deutsche Demokratische Republik (East Germany, English abbr.: GDR, qv.)
- DDS - Doctor of Dental Surgery
- DDT - dichloro-diphenyl-trichloroethane (insecticide) - Dynamic Debugging Tool (computing)
- DEA - Drug Enforcement Agency
- DEC - Digital Equipment Corporation - Disasters Emergency Committee - Department of Environmental Conservation
- DH, DD, DS - dear husband, dear daughter, dear son (increasingly prevalent on social mailing lists, blogs, and bulletin boards)
- DHSS - Department of Health and Social Security
- DIMM - double in-line memory module (computing)
- DIP - dual in-line package (electronics)
- DIY - do it yourself
- DMA - direct memory access (computing)
- DMD - Doctor of Dental Medicine
- DMZ - demilitarized zone
- DNA - DeoxyriboNucleic Acid - Douglas Adams
- DND - Do Not Disturb - Department of National Defense
- DOA - Dead On Arrival
- DPCO - double-pole change over
- DPDT - double-pole double-throw
- DPRK - Democratic People's Republic of Korea
- DPST - double-pole single-throw
- DRA - Democratic Republic of America
- DRAM - dynamic random access memory (computing)
- DRC - Democratic Republic of the Congo
- DREA - Defense Research Establishment Atlantic
- DRL - daytime running lights - Dorman Roberts Ltd.
- DTE - Down to earth
- DTL - diode-transistor logic (electronics)
- DTRA - Defence Threat Reduction Agency
- DUI - Driving Under the Influence - Data Use Identifier - Data Use Institute - Davis Unified Ignition - Diving Unlimited International - Documento Único de Identidad - Documento Unico de Importación - Duke University Improv
- DVD - Digital Versatile Disk (was Digital Video Disk)
- DVM - Doctor of Veterinary Medicine
- DWI - Driving While Intoxicated/Impaired - Dance With Intensity - Danish West Indies - Diffusion-weighted imaging - Direct water injection - Disaster Welfare Inquiry - Drinking Water Inspectorate
- EAFUS - "Everything" Added to Food in the United States (FDA list)
- EBCDIC - Extended Binary Coded Decimal Interchange Code (computing)
- EBE - extraterrestrial biological entity
- EBW - exploding bridgewire
- ECL - emitter coupled logic (electronics)
- ECS - Extended Chip Set (computing)
- EDS - Electronic Data Systems
- EEC - European Economic Community (predecessor of the EU, qv.)
- EFF - Electronic Frontier Foundation
- e.g. - example gratis (Latin, roughly "for example", "for instance")
- ELF - Earth Liberation Front - Endangered Language Fund - Eritrean Liberation Front - Executable and Linkable Format - Extremely Low Frequencies
- EMF - electromotive force
- EMO - emergency-measures organisation
- EMP - electromagnetic pulse
- ENE - east northeast
- EPL - English Premier League
- ERA - earned run average - Engineering Research Associates - Equal Rights Amendment
- ERCIM - European Research Consortium for Informatics and Mathematics
- ESA - European Space Agency
- ESE - east southeast
- ESP - Extra-Sensory Perception
- ETA - estimated time of arrival - Euzkadi Ta Azkatasuna
- etc - latin "et cetera" (and remaining)
- ETLA - Extended TLA
- EU - European Union
- EULA - End-User License Agreement
- EVA - extra-vehicular activity
- FAAQ - Frequently Asked and Anticipated Questions (see also FAQ)
- FAO - Food and Agriculture Organization
- FAQ - Frequently Asked Questions
- FASEB - Federation of American Societies for Experimental Biology
- FBI - Federal Bureau of Investigation
- FCM - Fogarty's Cove Music - Federation of Canadian Municipalities
- FDR - Franklin Delano Roosevelt - Flight data recorder
- FEMA - Federal Emergency Management Agency
- FIU - Florida International University
- FLIR - forward looking infrared (sensor)
- FLK - Funny-Looking Kid (medical diagnosis in-joke)
- FM - frequency modulation (electronics)
- FMSF False Memory Syndrome Foundation
- FPS - First person shooter (computer/video games)
- FSF - Free Software Foundation
- FST - Finlands Svenska Television (Finland's Swedish-language television)
- FTL - Faster Than Light
- FUD - Fear, Uncertainty & Doubt (marketing strategy)
- FWI - French West Indies
- FWIW - For What It's Worth
- FYI - For Your Information
- FYROM - Former Yugoslav Republic of Macedonia
G,H,I
- GCD - see entry
- GCF - greatest common factor
- GDP - gross domestic product
- GDR - German Democratic Republic
- GE - General Electric - Genetic Engineering (see GM)
- GEOS - Graphical Environment Operating System
- GEV - Ground Effect Vehicle
- GFCI - ground fault circuit interrupter (aka GFI)
- GFDL - GNU Free Documentation License
- GFI - ground fault interrupter (aka GFCI)
- GFY - Internet chat acronym, "good for you", or "go fuck yourself", depending on the context
- GI - galvanised iron - government issue - gastro-intestinal
- GL - Grenade Launcher
- GM - GameMaster (role-playing terminology) / Genetically Modified / General Motors / Guru Meditation
- GmbH - Gesellschaft mit beschränkter Haftung (German, roughy "Inc" or "Ltd")
- GMO - Genetically modified organism
- GOP - Grand Old Party (United States Republican Party)
- GPIB - General-Purpose Instrumentation/Interface Bus
- GPS - Global Positioning System
- GRAS - Generally Regarded as Safe (FDA list)
- GST - Goods and Services Tax (Canada)
- GSOH - Good sense of humour
- GT - Gran Turismo
- GUI - graphical user interface
- GUT - grand unification theory
- HCF - highest common factor
- HDD - hard disk drive - high-density disk
- HEPA - High-efficiency particulate air (filter)
- HKS - hyperkinetic syndrome
- HMCE - Her Majesty's Customs and Excise
- HMCS - Her/His Majesty's Canadian Ship
- HMO - Health Management Organization
- HMP - Her (or His) Majesty's Prison
- HMS - Her (or His) Majesty's Ship (see Royal Navy)
- HMSO - Her (or His) Majesty's Stationery Office
- HPGL - Hewlett-Packard Graphics Language
- HPIB - Hewlett-Packard Instrumentation/Interface Bus
- HPV - Human papilloma virus
- HQ - Headquarters
- HRH - His/Her Royal Highness
- HSS - High-Speed Steel
- HST - see entry
- HSV - herpes simplex virus - hue saturation value (colour model)
- HTML - Hypertext Markup Language
- HVP - hydrolized vegetable protein - HarborView Properties - High Vacuum Process
- IAAF - International Association of Athletics Federations
- IAAL - I am a lawyer
- IAEA - International Atomic Energy Agency
- IAI - International African Institute
- IANA - Internet Assigned Numbers Authority
- IANAL - I am not a lawyer
- IATA - International Air Transport Association
- ICAO - International Civil Aviation Organization
- ICBM - intercontinental ballistic missile
- ICC - International Criminal Court
- ICP - Insane Clown Posse
- IDF - Israel Defence Forces
- ie - id est (Latin, roughly "that is")
- IEEE - Institute of Electrical and Electronics Engineers
- IFO - Identified flying object
- IHR - Institute for Historical Review
- IIRC - If I recall correctly
- IIT - Indian Institutes of Technology
- ILC - International Law Commission
- ILO - International Labour Organisation
- IMF - International Monetary Fund
- IMHO - In My Humble Opinion
- IMO - International Maritime Organization - In My Opinion
- IMRI - Industrial Membrane Research Institute - Information Management Research Institute - International Market Research Information - Institut pour le Management de la Recherche et de l'Innovation - intraoperative magnetic resonance imaging
- INC - Iraqi National Congress
- INLA - Irish National Liberation Army
- INRI - Iesus Nazarenus Rex Iudæorum (Latin, Jesus of Nazareth King of the Jews)
- IPN - Instytut Pamieci Narodowej (Institute for National Memory)
- IQ - Intelligence Quotient
- IR - Infrared
- IRA - Individual Retirement Account (legally, Individual Retirement Arrangement) - Irish Republican Army
- IRC - Internet relay chat
- IRO - International Refugee Organisation
- IRS - Internal Revenue Service
- ISA - Individual Savings Account - industry standard architecture - Instruction Set Architecture - International Seabed Authority
- ISO - International Organization for Standardization
- ITN - Independent Television News (British TV news company)
- ITU - International Telecommunication Union (yet to be established)
J,K,L
- JAMA - Journal of the American Medical Association
- JCS - Joint Chiefs of Staff
- JDL - Jewish Defense League
- JFK - John Fitzgerald Kennedy
- JRA - Japanese Red Army
- JW - Jehovah's witness
- KARNAC - Knowledge Aided Retrieval in Activity Context
- KCK - Kansas City, Kansas
- KCMO - Kansas City, Missouri (pronounced "K-C-Moe")
- KFC - Kentucky Fried Chicken
- KGB - Komitet Gosudarstvennoy Bezopasnosti (Committee for State Security - Soviet Intelligence Service
- KIA - Killed In Action
- KISS - Keep It Simple, Stupid
- KKK - Ku Klux Klan
- LANL - Los Alamos National Laboratory
- LATA - Local Access Transport Area
- LBGT - Lesbian, Gay, Bisexual, Transgender
- LBJ - Lyndon Johnson - "Lady Bird" Johnson - Lightbulb joke
- LCM - least common multiple
- LDAP - Lightweight Directory Access Protocol
- LDS - Latter Day Saint
- LEC - Local Exchange Carrier
- LED - Light Emitting Diode
- LGB - Lesbian, Gay, Bisexual
- LGM - little green men
- LIFO - Last In First Out
- LLC - limited liability company
- LLP - limited liability partnership
- LMAO - Laughing my a** off.
- LMS - London Mathematical Society
- LNG - liquefied natural gas
- LOL - Laughing Out Loud
- LPG - liquefied petroleum gas
- LSE - London School of Economics - London Stock Exchange
- LSI - Large-Scale Integration
M,N,O
- MAA - Mathematical Association of America
- MAD - magnetic anomaly detector - mutual assured destruction
- MADD - Mothers Against Drunk Driving - Myoadenylate deaminase deficiency
- MASH - Mobile army surgical hospital
- MBTA - Massachusetts Bay Transit Authority
- MCD - minimal cerebral dysfunction
- MDF - main distribution frame - medium-density fibreboard
- MG - Machine gun
- MHz - Megahertz
- MIA - Missing in action
- MIT - Massachusetts Institute of Technology; Milli Istihbarad Teskilati (Intelligence service of Turkey)
- MITS - see entry
- MLA - member of legislative assembly
- MLB - Major League Baseball
- MLS - Major League Soccer
- MMU - Manned Maneuvering Unit
- MND - Motor Neurone Disease
- MO - modus operandi
- MOAB - mother of all bombs
- MOPE - Most Oppressed People Ever (politics)
- MOSFET - metal-oxide-semiconductor field-effect transistors
- MP - Member of Parliament - military police - magic points
- MRI - magnetic resonance imaging
- MS - Master of Science - Microsoft (sometimes M$) - Multiple sclerosis
- MSG - Monosodium glutamate
- MSIE - Microsoft Internet Explorer
- MTR - Main and Tail Rotor (helicopter type)
- MTS - Michigan Terminal/Timesharing System - multichannel television sound - Multi-Technical Services
- MTV - Music TeleVision; MainosTeleVisio (Finnish commercial TV company)
- n/a - not available / Not applicable
- NAACP - National Association for the Advancement of Colored People
- NAIRU - Non Accelerating Inflation Rate of Unemployment
- NAMBLA - North American Man-Boy Love Association - National Association of Marlon Brando Look-Alikes
- NASA - Nat'l Aeronautics and Space Administration - Never A Straight Answer
- NATO - North Atlantic Treaty Organization
- NB - nota bene - New Brunswick
- NBA - National Basketball Association
- NBC - Nuclear/Biological/Chemical - National Broadcasting Corporation
- NC - network computer - non-consensual - normally closed - North Carolina
- NCAA - National Collegiate Athletic Association
- NDP - New Democratic Party
- NE - northeast
- NET - National Educational Television
- NFER - National Foundation for Educational Research
- NFL - National Football League
- Nfld - Newfoundland
- NG - natural gas - next generation
- NGO - non-governmental organization
- NHANES - National Health and Nutrition Examination Survey
- NHL - National Hockey League
- NIH - National Institutes of Health - Not Invented Here
- NIEHS - Natinal Institute of Environmental Health Sciences
- NIMH - nickel metal hydride - National Institute of Medical Herbalists - National Institute of Mental Health
- NIST - National Institute of Standards and Technology
- NLP - Natural Language Processing or Neuro Linguistic Programming
- NNE - north northeast
- NNW - north northwest
- NO - normally open
- NORML - National Organization for the Reform of Marijuana Laws
- NPC - Non-Player Character (roleplaying terminology) / National Provincial Championship (New Zealand rugby competition)
- NPD - Nationaldemokratische Partei Deutschlands (German)
- NPOV - Neutral point of view
- NPR - National Public Radio
- NRTA - National Retired Teachers Association - National Rat Terrier Association - Northwest Regional Transmission Association - National Retail Tenants Association
- NSA - National Security Agency
- NTSC - National Television Standards Committee
- NW - northwest
- NWFZ - Nuclear-Weapons-Free Zone
- NYSE - New York Stock Exchange
- NZ - New Zealand
- OAC - on approved credit
- OAU - Organization for African Unity
- OBE - Order of the British Empire
- OCR - optical character recognition
- OCS - see entry
- OED - Oxford English Dictionary
- OEM - Original Equipment Manufacturer
- OJ - orange juice / O. J. Simpson
- OO - object oriented - over & out
- OOP - object-oriented programming
- OSB - oriented-strand board
- OSI - Office of Strategic Influence / Ontario Swine Improvement / Open Source Initiative / Open systems interconnect
- OSS - Organization of Strategic Services (forerunner of CIA)
- OTOH - On The Other Hand
P,Q,R,S
- PABX - Private Automated Branch Exchange (company phone system)
- PARC - Palo Alto Research Center
- PBS - Public Broadcasting Service
- PBX - Private Branch Exchange (company phone system)
- PC - Personal Computer; Player Character (roleplaying terminology); Politically Correct(ness)
- PCB - see entry
- PCC - Presidents Conference Committee
- PCMCIA - Personal Computer Memory Card Interface Association / People Can't Memorise Computer-Industry Acronyms
- PCP - phencyclidine - pneumocystis carinii pneumonia - Probabilistically Checkable Proof
- PDA - Public display of affection - personal digital assistant - push-down automaton
- PDF - portable document format
- PDN - pull-down network
- PDQ - pretty damn quick (?)
- PDRY - People's Democratic Republic of Yemen
- PET - positron emission tomography - Personal Electronic Transactor
- PETA - pentaerythritol triacrylate - People Eating Tasty Animals - People for the Ethical Treatment of Animals
- PFO - Pissed, Fell Over (medical diagnosis in-joke)
- PIN - Personal identication Number
- PINF - People In Need Foundation (Czech charitable organization)
- PIPA - Program on International Policy Attitudes
- PLC - (British) public limited company
- PLO - Palestine Liberation Organization
- PM - post meridian - Prime Minister - phase modulation - Perry Mason
- PNAC - Project for the New American Century
- PNG - Portable Network Graphic - Papua New Guinea
- PNP - Partido Nuevo Progresista - plug 'n' play - positive negative positive
- POP - Point of Presence - Post Office Protocol
- POTS - Plain Old Telephone Service, also PANS - Pretty Advanced (or Awsome) Network Services
- PPP - Point-to-Point Protocol / Purchasing Power Parity
- PRC - People's Republic of China
- PSA - Prostate specific antigen - Production Services Association - Paralysis Society of America - Pharmaceutical Society of Australia - Public Service Association - Public Service Announcement - pressure-sensitive adhesive
- PTA - parent-teacher association
- PTUI - plain-text user interface
- PUG - PET Users Group
- PUN - pull-up network
- PVC - permanent virtual circuit - polyvinyl chloride - premature ventricular contraction
- PWP - Plot, What Plot? (in online fiction, especially fanfic or erotic fiction, to denote plotless, um, "feel-good" stories)
- PWR - pressurized water reactor
- QC - Queen's Counsel
- QCA - Qualifications and Curriculum Authority - Quality Council of Alberta
- QCD - quantum chromodynamics
- QED - Latin "quid es demonstrata" (that proves it) - quantum electrodynamics
- QSL - Québec sign language
- qv - Latin "quod vide" (which see)
- R&B - Rhythm and Blues
- RA - right ascension
- RAF - Royal Air Force; Red Army Faction
- RAM - random-access memory
- Rap - Rhythm and poetry
- RBI - Runs batted in
- RBOC - Regional Bell operating company ("Baby Bell")
- RC - see entry
- RCA - Radio Corporation of America
- RCAF - Royal Canadian Air Force
- RCCO - Royal Canadian College of Organists
- RCMP - Royal Canadian Mounted Police
- REACT - Remote Electronically Activated Control Technology
- REAM - Retired Educators Association of Minnesota
- RFC - request for comments
- RGB - red green blue (colour model)
- RIAA - Recording Industry Association of America
- RIP - Rest in Peace (requiescant in pace)
- RMS - Royal Mail Ship (eg RMS Titanic) - Root-mean-square - Richard Stallman - Rate-monotonic scheduling
- RNA - Ribonucleic Acid
- ROC - Republic of China
- ROFL(MAO) - Rolling On the Floor Laughing (My A** Off)
- ROM - read-only memory
- ROV - remotely operated vehicle
- RP - role-playing
- RPG - role-playing game; Rocket Projectile Gun; Rocket Powered/Propelled Grenade
- rpm - Revolutions Per Minute; Red Hat Package Manager
- RPN - Reverse Polish Notation
- rps - Revolutions Per Second
- RRSP - Registered Retirement Savings Plan (Canada; roughly equivalent to the IRA in the USA)
- RTF - Rich Text Format
- RTL - resistor-transistor logic
- RUC - Royal Ulster Constabulary
- SA - Sturmabteilung (Storm Detachment, forerunner and rival of SS)
- SAD - Seasonal Affective Disorder
- SALT - Strategic Arms Limitation Treaty
- SAM - sequential-access memory - surface-to-air missile - Sociedad Aeronáutica de Medellín
- SAR - Search and Rescue - special administrative region
- SARS - Severe Acute Respiratory Syndrome
- SAS - Special Air Service; Scandinavian Airline Systems
- SAT - formerly Scholastic Aptitude Test and Scholastic Assessment Test; now known solely by the initials
- SATB - soprano alto tenor bass
- SBS - Special Boat Service; Special Broadcasting Service
- SCRAM - safety control rod axe man
- SCSI - small computer system interface
- SDI - see entry
- SDP - Social Democratic Party (European politics)
- SE - southeast
- SEC - Securities and Exchange Commission / Southeastern Conference
- SETI - Search for Extraterrestrial Intelligence
- SF - San Francisco - science fiction
- SGML - Standard Generalised Markup Language
- SI - Système International - Socialist International - Sports Illustrated
- SIAM - Society for Industrial and Applied Mathematics
- SIG - Special Interest Group
- SIMM - single in-line memory module
- SIS - Secret Intelligence Service (also known as MI6)
- SLA - Symbionese Liberation Army
- SMDR - Station Message Detail Recording
- SMG - Submachine Gun
- SMU - Southern Methodist University
- SNAFU - Situation Normal (All Fouled Up)
- SNCF - Société National des Chemins de Fer Français (French Railways)
- SOE - Special Operations Executive (WW2 British organization)
- SOL - S**t Out of Luck
- SOV - Single occupant vehicle
- SPCO - single-pole change over
- SPDT - single-pole double-throw
- SPQR - Senatus Populus Que Romanus
- SPST - single-pole single-throw
- SRAM - Static Random Access Memory
- SRB - solid rocket booster
- SS - Schutzstaffel (elite guard) - Secret Service - Spanish ship - stainless steel - Stockholm Skins - Super Sport
- SSDD - same shit, different day - single-sided double-density
- SSE - south southeast
- SSRI - Social Systems Research Institute - Selective serotonin reuptake inhibitor
- SSW - south southwest
- STOL - Short Take Off and Landing
- STOVL - Short Take Off and Vertical Landing
- STP - standard temperature and pressure
- SUB - student-union building
- SVO - subject, verb, object
- SW - southwest
- SWAPO - South West African People's Organization
T,U,V
- TATT - Tired All The Time (medical diagnosis in-joke)
- TCP - Transmission Control Protocol - trichlorophenol
- TCU - Texas Christian University
- TGIF - Thank God it's Friday
- TGV - Train à Grande Vitesse (high-speed train) - Tanjong Golden Village - Test Generation with Verification
- TLA - Three-Letter Acronym
- TLC - tender loving care - The Learning Channel
- TLD - top-level domain
- TM - trademark - Turing machine
- TMR - Twin Main Rotors (helicopter type)
- TSR - see entry
- TTL - Transistor-transistor logic
- TTYL - Internet chat acryonym, "talk to you later"
- TUG - TeX Users Group
- TUI - text user interface
- TUNS - Technical University of Nova Scotia
- TWAT - The War Against Terror
- UBC - united baptist church - University of British Columbia
- UÇK - acronym for two Albanian guerilla movements
- UCLA - University of California Los Angeles
- UFO - Unidentified Flying Object
- UHF - ultra high frequency
- UHMW - ultra-high molecular weight
- UL - Underwriters Laboratories
- UN - United Nations
- UNCF - United Negro College Fund
- UNHCR - United Nations High Commission for Refugees
- UNLV - University of Nevada, Las Vegas
- UNSM - Union of Nova Scotian Municipalities
- UPI - United Press International
- UPS - United Parcel Service - uninterruptible power supply
- UPU - Universal Postal Union
- URI - uniform resource identifier
- URL - uniform resource locator
- USA - United States of America
- USAF - United States Air Force
- USAPATRIOT - Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism
- USC - United States Code / University of Southern California / University of South Carolina
- USDOE - United States Department of Energy
- USGS - United States Geological Survey
- USS - United States ship
- USSR - United Soviet Socialist Republics (ie. Soviet Union)
- UV - ultraviolet
- VAT - value-added tax
- VHF - very high frequency
- VIP - very important person
- VLSI - Very-large-scale integration
- VNS - vagus nerve stimulation
- VP - vice-president
- VSO - Voluntary Services Overseas
- VTOL - Vertical Takeoff & Landing
- VV - Via Voice - Village Voice
W,X,Y,Z
- W3C - World Wide Web Consortium
- WASP - white anglo-saxon protestant
- WB - Warner Brothers
- WC - Winston Churchill - water closet
- WCL - World Confederation of Labour
- WFP - World Food Program
- WHO - World Health Organization
- WIPO - World Intellectual Property Organization
- WMO - World Meteorological Organization
- WNW - west northwest
- WOLOG - without loss of generality
- WRT - with respect to
- WSJ - Wall Street Journal
- WSW - west southwest
- WTC - World Trade Center
- WTO - World Trade Organization
- WW1 (or WWI) - World War One
- WW2 (or WWII) - World War Two
- WWE - World Wrestling Entertainment
- WWF - World Wildlife Fund; World Wrestling Federation
- WWW - World Wide Web
- YMCA - Young Men's Christian Association
- YMMV - Your Mileage May Vary
- YWCA - Young Women's Christian Association
- ZOPFAN - Zone of Peace, Freedom and Neutrality
See also: List of acronyms, Wikipedia:Disambiguation/Abbreviations, Abbreviations used in CIA World Factbook