| Abbreviation | Definition |
|---|---|
| ATB | All Terrain Boarding |
| ATC | Artist Trading Card |
| ATCL | l'Automobile et Touring Club du Liban |
| ATLAS | All Terrain Launch Aviation System |
| ATLU | Addicted Tea Lovers United |
| ATSU | Association of Time-Sharing Users |
| AU | Athletic Union |
| AVA | Alliance of Valiant Arms |
| AVC | Atari Video Club |
| AVS | Australian Vegetarian Society |
| AWOL | Arkansas Women On the Loose |
| B&M | Bolliger And Mabillard |
| BAAS | Bristol and Avon Archaeological Society |
| BABES | Bay Area Bug Eating Society |
| BABT | Bay Area Bottom Timers |
| BABT | Bay Area Brewpub Tour |
| BADC | British Academy of Dramatic Combat |
| BAH | Blatant Aimbot Hacks |
| BARR | Bay Area Rum Runners |
| BAS | The Bovine Appreciation Society |