| 5G | 5Th Generation Mobile Network |
| AAA | American Automobile Association |
| AAAT | Area, Aptitude, Attitude, Traffic |
| AAC | Advanced Audio Coding |
| AADHYA | First Power Or The Beginning |
| AARP | American Association Of Retired Persons |
| AAT | Architecture Aptitude Test / Association Of Accounting Technicians |
| ABA | Applied Behavior Analysis |
| ABACUS | Abundant Beads Addition Calculation Utility System |
| ABIDE | Association Of Body Image And Disordered Eating |
| ABM | Activity-Based Management |
| ABNORMAL | |
| AC | Alternating Current |
| ACA | Associate Chartered Accountant / Affordable Care Act |
| ACAS | Advisory, Conciliation And Arbitration Service / Air Cargo Advance Screening |
| ACD | Automatic Call Distributor |
| ACE | Angiotensin-Converting Enzyme |
| ACL | Anterior Cruciate Ligament |
| ACLS | Advanced Cardiovascular Life Support |
| ACO | Accountable Care Organizations |
| ACST | Admission Cum Scholarship Test / Australian Central Standard Time |
| ACT | American College Testing |
| ADAC | Allgemeiner Deutscher Automobil-Club / Active Directory Administrative Center |
| ADE | Aeronautical Development Establishment / Algebraic Differential Equation |
| ADIDAS | Adolf "Adi" Dassler |
| ADN | Application Delivery Network / Associate Degree In Nursing |
| ADND | Advanced Dungeons And Dragons |
| ADP | Automatic Data Processing/ Adenosine Triphosphate |
| ADR | Alternative Dispute Resolution |
| ADSS | All Dielectric Self-Supporting |
| ADT | Abstract Data Type / Admission, Discharge, And Transfer. |
| ADU | Accessory Dwelling Unit |
| ADVENT | Advanced Value Engineering & Technology |
| AECB | Acute Exacerbation Of Chronic Bronchitis |
| AEM | Adobe Experience Manager |
| AFFIRMATION | |
| AGAPE | Unconditional Love |
| AGL | Acute Granulocytic Leukemia |
| AGM | Annual General Meeting |
| AHA | Alpha-Hydroxy Acid |
| AIA | American Insurance Association |
| AIATS | All India Aakash Test Series For Neet/Aiims |
| AIDS | Human Immunodeficiency Virus Infection And Acquired Immune Deficiency Syndrome |
| AIG | American International Group, Inc |
| AIRBNB | Air Bed And Breakfast |
| AKASH | Ability, Knowldge, Attitude, Skills, Habits |
| ALLITERATION | |
| ALLY | |
| AMA | American Medical Association |
| AMC | Annual Maintenance Contract |
| AMEX | American Express Company |
| AMG | Mercedes-Aufrecht, Melcher And Großaspach |
| AMI | Advanced Metering Infrastructure / Acute Myocardial Infarction |
| AML | Acute Myeloid Leukemia |
| AMP | Ampere |
| ANALYTICAL | |
| ANECDOTE | |
| ANTI-SEMITIC | |
| AODA | Accessibility For Ontarians With Disabilities Act |
| APFDC | Andhra Pradesh Forest Development Corporation Limited |
| APM | Application Performance Monitoring |
| APME | Asia Pacific And Middle East / Acute Postinfectious Measles Encephalitis |
| APPLE | Asian Passenger Payload Experiment |
| APSC | Assam Public Service Commission / Advanced Photo System Type-C |
| AR | Augmented Reality |
| ARMY | Alert Regular Mobility Young |
| ASC | Army Service Corps / Accounting Standards Codification |
| ASCVD | Atherosclerotic Cardiovascular Disease |
| ASF | As Fuck |
| ASI | Assistant Sub-Inspector |
| ASIC | Application-Specific Integrated Circui |
| ASIS | American Society For Industrial Security |
| ASME | The American Society Of Mechanical Engineers |
| ASOS | As Seen On Screen |
| ASPCA | American Society For The Prevention Of Cruelty To Animals |
| ASRS | Automated Storage & Retrieval System |
| ATCC | American Type Culture Collection |
| ATNT | American Telephone And Telegraph |
| ATP | Adenosine Triphosphate |
| ATS | Anti-Terror Squad |
| AUDIT | Automated Data Input Termina |
| AURA | Accounting Unit Reporting Application |
| AVF | Arteriovenous Fistula |
| AVM | Arteriovenous Malformation |
| AWS | Amazon Web Services |