Abbreviations & Acronyms with A

Abbreviation:
An abbreviation is a shortened form of a word or a phrase (group of words).
The result of abbreviation is a reduced form or abridgement of writing. They are commonly used because they save time and space.
As said by John Horne Tooke, “Abbreviations are the wheels of language, the wings of Mercury.
Examples:
ATM = Automated Teller Machine
BBC = British Broadcasting Corporation
Acronym:
It is a word formed from the initial letters of the several words in the name and pronounced as one word.
Examples:
NASA = National Aeronautics and Space Administration (USA)
AIDS = Acquired Immune Deficiency Syndrome.
Most Common Abbreviations & Acronyms with letter A
A
A | Academician / adenine (biology in DNA sequences) / angstrom (Physics) / for adults (a film certificate) |
a | accepted (on bills of exchange) |
AA | Automobile Association / Anti-aircraft / Alcoholics Anonymous |
AAA | Amateur Athletic Association / American (Australian) Automobile Association / Anti-aircraft artillery (US) |
AAAS | American Association for the Advancement of Science |
AARP | American Association of Retired Persons |
AAU | Amateur Athletic Union |
AB | Able (seaman) / Artium Baccalaureus Bachelor of Arts (Latin) equivalent to BA |
ABA | Amateur Boxing Association / American Bar Association (US) / American Booksellers’ Association (US) |
ABC | American Broadcasting Corporation / Australian Broadcasting Corporation (formerly Commission) |
ABH | Actual bodily harm (minor and less serious injury such as bruising) |
ABH | Anti-ballistic missile |
ABS | Anti-lock braking system (for motor vehicles) / Acrylonitrile-butadiene-styrene, a hard composite plastic |
ABTA | Association of British Travel Agents |
ABV | Alcohol by volume |
A/C | Account current / Air-conditioned (Air-conditioning) |
AC | Air-conditioned/Air-conditioning / Aircraftman / Alternating current (Electricity) / Athletic club / ante Christum ‘before Christ’ (Latin) |
ACAS | Advisory, Conciliation, and Arbitration Service |
A/D | Analog to digital (Electronics) |
AD | Anno Domini (in the year of Our Lord – Latin) |
ADA | Adenosine deaminase |
ADC | Aide-de-camp / Analogue–digital converter |
ADD | Attention deficit disorder (Medical) |
ADF | Automatic direction-finder, a device used by pilots to aid navigation |
AFAIK | As far as I Know |
AFB | Air Force Base |
AFC | Air Force Cross (UK) / Association Football Club |
AFDC | Aid to Families with Dependent Children (US), (a welfare benefit paid by the federal government) |
AFB | Air Force Base |
AFL | Australian Football League |
AFM | Air Force Medal |
AG | Adjutant General / Attorney General |
Ag | Antigen (Biochemistry) |
AGC | Automatic Gain Control (Electronics) |
AGM | Annual General Meeting |
AGR | Advanced gas-cooled (nuclear) reactor |
ADH | Antidiuretic hormone (Medical) |
ADHD | Attention deficit hyperactivity disorder |
Adj. / adj. | adjective (Grammar) / adjutant (Military) |
ADP | Adenosine diphosphate (Biochemistry) / Automatic data processing |
ADR | Alternative dispute resolution (Law) / American depository receipt (US Stock Exchange) |
ADSL | Asymmetric (or asynchronous) digital subscriber line (or loop) (Computing & Telecommunications) |
A & E | Accident and Emergency |
AEEU | Amalgamated Engineering and Electrical Union |
AEF | American Expeditionary Forces (esp. in Europe) during the First World War |
AER | Annual Equivalence Rate (of a compound interest rate paid annually) |
AEU | Amalgamated Engineering Union |
AF | Audio Frequency / autofocus |
AGW | Anthropogenic Global Warming |
AH | In the year of the Hegira (Muslim Calendar) |
AHA | Alpha-Hydroxy Acid |
AI | Amnesty International / Artificial Intelligence / Artificial Insemination |
AID | Artificial Insemination by Donor |
AIDS | (acronym) Acquired Immune Deficiency Syndrome |
AIH | Artificial Insemination by Husband |
AIIMS | (both abbreviation & acronym) — All India Institute of Medical Sciences |
AIM | Alternative Investment Marketing (UK) |
AIR | (both abbreviation & acronym) — All India Radio |
AK | Alaska (US) (in official postal use) |
aka | also known as |
AL | Alabama (US) (in official postal use) / American League (in baseball) |
Ala. | Alabama |
ALA | All Letters Answered (used in personal advertisements) |
Alas. | Alaska |
a.m. | ante meridiem (before noon) |
AM | Amplitude Modulation |
A & M | Hymns Ancient and Modern |
AMU | Aligarh Muslim University |
ANC | African National Congress |
AND | Andorra (International vehicle Registration) |
AP | Associated Press |
APB | all-points bulletin |
APC | armored personnel carrier |
APEC | Asia Pacific Economic Cooperation |
Apoc. | Apocalypse / Apocrypha |
Apocr. | Apocrypha |
AR | Arkansas (US) (in official postal use) / Autonomous Republic |
A & R | artist(s) & repertoire (or recording) |
ARA | Associate of the Royal Academy |
AS | Anglo-Saxon |
ASA | Advertising Standards Authority / Amateur Swimming Association / American Standards Association (esp. in film-speed specification) |
ASAP | as soon as possible |
ASB | Alternative Service Book |
ASCII | American Standard Code for Information Interchange (Computing) |
ASD | autistic spectrum disorder |
ASDIC | (acronym) Allied Submarine Detection Investigation Committee |
ASEAN | (both abbreviation & acronym) Association of Southeast Asian Nations |
ASH | Action on Smoking and Health (UK) |
ASI | airspeed indicator |
ASIC | application specific integrated circuit (Electronics) |
ASLEF | Associated Society of Locomotive Engineers and Firemen (UK) |
ASM | air-to-surface missile / assistant stage manager |
ASP | application service provider |
ASSR | Autonomous Soviet Socialist Republic |
Asst. | Assistant |
AST | Atlantic Standard Time |
ASV | American Standard Version |
ATB | all-terrain bike |
ATC | air traffic control/air traffic controller / Air Training Corps (Britain) |
ATE | automated test equipment |
ATF | (Federal Bureau of) Alcohol, Tobacco, and Firearms |
ATM | Automated Teller Machine / asynchronous transfer mode (Electronics) |
ATOL | Air Travel Organizer’s License (UK) |
ATP | automatic train protection (UK) / adenosine triphosphate (Biochemistry) |
Attn/attn | attention/for the attention of (written on an envelope or on the top of a letter or fax) |
ATV | all-terrain vehicles (USA) |
AU / a.u. Au | African Union / astronomical unit/s aurum (Latin) (the chemical element gold) |
AUC | 1. ab urbe condita (Latin) (from the foundation of the city i.e. Rome) 2. Anno Urbis Conditae (in the year of the foundation of the city) |
AUEW | Amalgamated Union of Engineering Workers (UK) (historical) |
AUS | Australia (international vehicle registration) |
AUT | Association of University Teachers (UK) |
AV | alternative vote (voting) / audio visual (teaching aids) / Authorized Version |
Ave | Avenue |
A/W | autumn/winter (referring to fashionwear) |
AWACS | (acronym) airborne warning and control system |
AWL/ AWOL | absent without leave absent without official leave (military) |
AWS | automatic warning system (Britain) |
AZ | Arizona (USA) (in official postal use) |
AZT | Azidothymidine (trademark) |