| AAR | Alliance for Aging Research |
|---|---|
| ABR | Applied Benefits Research |
| ACRP | Association of Clinical Research Professionals |
| ACU | Asian Clearing Union (skr.) |
| ADL | Advanced Distributed Learning |
| ADR | Applied Data Research |
| AEI | Association of Early Intervention |
| AES | Aircraft Earth Station |
| ALEARDI | taliansky spisovateľ (Aleardo, 1812-1878) |
| ALFA | prvé písmeno gréckej abecedy, začiatok, pôvod, začiatok a koniec niečoho, druh nukleárneho žiarenia |