| A&D | Aerospace and Defence (or, Aerospace and Defense) ✓ Verified | Military, Industry, Aviation |
| A&P | Administrative and Personnel✓ Verified | Business, Company, Department |
| A-VO2 | Arteriovenous Oxygen✓ Verified | Measurement Unit, Medical |
| A/D | Analog/Digital✓ Verified | Signal, Technology |
| A/DACG | Arrival/Departure Airfield Control Group✓ Verified | Military, Air Force |
| AA | Alcoholics Anonymous✓ Verified | Group, Health, Organization |
| AAAAAA | American Association Against Acronym Abuse Anonymous✓ Verified | Communication |
| AAAAI | American Academy of Allergy, Asthma & Immunology✓ Verified | Education, Academy, Medical, Organization |
| AAABEM | American Association of Acupuncture and Bio-Energetic Medicine✓ Verified | Association, Medical, Organization |
| AAACC | African American Art & Culture Complex✓ Verified | Facility |
| AAAD | Area Agency on Aging and Disability✓ Verified | Agency, Group, Organization |
| AAAD | Aromatic L-Amino Acid Decarboxylase✓ Verified | Medical, Chemistry, Chemical Compound |
| AAAI | American Aerobic Association, International✓ Verified | Association, Health, Fitness, Organization, Sports |
| AAAI | Associated Aerospace Activities, Inc.✓ Verified | Business, Company |
| AABA | Association for Accountancy & Business Affairs✓ Verified | Association, Business |
| AACA | American Anti-Corruption Act✓ Verified | Legal, Policy, Politics |
| AACCCM | Anglo-American Cataloguing Committee for Cartographic Materials✓ Verified | Committee, Group, Library, Science |
| AACE | Academy for Advanced and Challenge Enthusiasts✓ Verified | Education |
| AACE | American Association of Cost Engineers✓ Verified | Association, Business |
| AACL | Albanian American Civic league✓ Verified | Group, Organization |
| AACL | Anti Ageing Conference London (or, Anti Aging Conference London)✓ Verified | Health, Meetings and Conferences |
| AACMI | Autonomous Air Combat Manoeuvring Instrumentation✓ Verified | Military, Air Force, Aviation, Technology |
| AACO | Arab Air Carriers' Organization✓ Verified | Association, Industry, Aviation, Organization |
| AACO | Auto Adaptive Contrast Optimisation✓ Verified | Technology |
| AACP | Above Anvil Cirrus Plume✓ Verified | Science, Meteorology |
| AACP | American Association of Colleges of Pharmacy✓ Verified | Association, Medical, Medicine |
| AACR | Anglo-American Cataloguing Rules✓ Verified | Education, Library |
| AACR | Animal-Assisted Crisis Response✓ Verified | Disaster, Health, Fitness, Medical, Safety |
| AACRAO | American Association of Collegiate Registrars and Admissions Officers✓ Verified | Education, College, University, Organization |
| AACS | Advanced Access Content System✓ Verified | Standards, Technology |
| AACS | Attitude and Articulation Control Subsystem✓ Verified | Engineering, Space, System, Technology, Space Travel, Spacecraft |
| AACT | Academy of Arts, Careers and Technology✓ Verified | Education, School |
| AACTI | Alberta Association of Colleges & Technical Institutes✓ Verified | Association, Education |
| AACTS | Aging & Adult Client Tracking System✓ Verified | Health, Fitness, Safety, Software |
| AACVPR | American Association of Cardiovascular and Pulmonary Rehabilitation✓ Verified | Association, Health, Medical |
| AAD | Africa Aerospace and Defence✓ Verified | Military, Defence, Event |
| AAD | Army Air Defence✓ Verified | Military, Air Force, Army, Defence |
| AADCP | Army Air Defense Command Post✓ Verified | Military, Air Force, Army, Defence |
| AADCP | ASEAN-Australia Development Cooperation Program✓ Verified | Program |
| AADI | Asian American Diabetes Initiative✓ Verified | Health, Medical, Program |
| AADL | Architecture Analysis & Design Language✓ Verified | Architecture, Software, Software Engineering, Technology |
| AADL | Automobile Association Developments Limited✓ Verified | Association, Organization, Automobile |
| AADM | Aniruddha's Academy of Disaster Management✓ Verified | Disaster, Education, Academy, Safety |
| AADM | Applicable Analysis and Discrete Mathematics✓ Verified | Education, Mathematics |
| AADSAS | Associated American Dental Schools Application Service✓ Verified | Education, Service |
| AAE | Advanced Automotive Electronics✓ Verified | System, Technology, Transport, Automobile |
| AAEA | Agricultural & Applied Economics Association✓ Verified | Agriculture, Association, Economics, Education |
| AAEA | American Agricultural Economics Association✓ Verified | Agriculture, Association, Economics, Education |
| AAEA | American Agricultural Editors' Association✓ Verified | Agriculture, Association |
| AAEB | Alumnae Association Executive Board✓ Verified | Association, Education, Institute |