| Abbreviation | Definition |
|---|---|
| ATCA | Airedale Terrier Club of America |
| ATCA | Antique Truck Club of America |
| ATCE | Automobile and Touring Club of Egypt |
| ATCF | Automobile and Touring Club of Finland |
| ATCJ | Airedale Terrier Club Of |
| ATCJ | Airedale Terrier Clubs of Japan |
| ATCJ | Audi TT Club Japan |
| ATCL | Automobile and Touring Club of Lebanon |
| ATCL | Automobile et Touring Club du Liban |
| ATCN | Airedale Terrier Club Nederland |
| ATCR | Aryarup Travel and Club Resort |
| ATDC | Anime Tea Drinking Club |
| ATFC | Aberystwyth Town Football Club |
| ATFC | Aldershot Town Football Club |
| ATM | Advanced Team Member |
| ATMC | American Traveler Motor Club |
| ATTC | Alameda Table Tennis Club |
| AUBC | Adelaide University Boat Club |
| AUC | American University Clubs |
| AUCC | Aichi University Computer Club |