| Acronym | Definition |
|---|
| AAR | Against All Risks |
| AAR | American Academy of Religion |
| AAR | Association of American Railroads |
| AAR | All-American Rejects (band) |
| AAR | After Action Report |
| AAR | After Action Review |
| AAR | Adobe Acrobat Reader (Adobe Systems, Inc.) |
| AAR | Aircraft Accident Report |
| AAR | Archives Audiovisuelles de la Recherche (French: Audiovisual Research Archives) |
| AAR | Air America Radio (talk radio network) |
| AAR | At Any Rate |
| AAR | American Association of Railroads |
| AAR | American Academy in Rome |
| AAR | Association for Aid and Relief (Tokyo, Japan) |
| AAR | All American Racers |
| AAR | Alkali-Aggregate Reaction |
| AAR | Approved Auto Repair (American Automobile Association) |
| AAR | Air-to-Air Refueling |
| AAR | Authority for Advance Rulings (India) |
| AAR | Automatic Alternate Routing |
| AAR | Association of Authors' Representatives, Inc. |
| AAR | Average Annual Rainfall |
| AAR | Accumulation-Area Ratio |
| AAR | Alliance for Aging Research |
| AAR | Action for Aboriginal Rights |
| AAR | Association for Automated Reasoning |
| AAR | Airport Acceptance Rate |
| AAR | Association to Aid Refugees (Japan) |
| AAR | Aarhus, Denmark - Tirstrup (Airport Code) |
| AAR | Airport Arrival Rate (capacity measure) |
| AAR | Active Array Radar |
| AAR | Administrative Adjustment Report |
| AAR | Antigen-Antibody Reaction |
| AAR | Alliance des Associations de Retraités (French: Alliance of Pensioners' Associations; Quebec, Canada) |
| AAR | American Association of Religion |
| AAR | Alfa, Access and Renova (Russian Oil Co) |
| AAR | Aortic Aneurysm Repair |
| AAR | Air to Air Receive |
| AAR | Air Augmented Rocket |
| AAR | Antigen-Antiglobulin Reaction |
| AAR | Affirmative Action Representative |
| AAR | Airworthiness Assurance Research and Development Branch (US FAA) |
| AAR | Automatic Adaptive Routing |
| AAR | Asiana Airlines Republic of Korea (ICAO code) |
| AAR | Atlas of Australian Resources |
| AAR | Army Area Representative |
| AAR | Acoustic Assessment Report |
| AAR | Adaptive Auto-Regressive |
| AAR | Action Aid Rwanda |
| AAR | Arrival and Assembly Railroads |
| AAR | Aktiebolaget Atomenergi Research |
| AAR | Agriculture Acquisition Regulation (US Department of Agriculture) |
| AAR | Army Achievement Award |
| AAR | Airborne Allergen Report |
| AAR | Automatic Answering and Recording |
| AAR | Audit Agenda Record |
| AAR | Authorized Area Representative |
| AAR | Agence Architecture Rey (French architecture agency) |
| AAR | Auto Analysis Stage (Infrared Space Observatory data analysis) |
| AAR | Aveize Auto Rétro (car club; France) |
| AAR | Area Access Rate |
| AAR | Automated Aerial Refueling (US NASA) |
| AAR | Alabama Association of Realtors (Montgomery, AL) |
| AAR | Apple Authorized Reseller |
| AAR | Age-Adjusted Rate (health statistics) |
| AAR | Annual Activity Report (various organizations) |