| Abbreviation | Definition |
|---|---|
| AST | Action Sports Team |
| ASU | All Stars United |
| ASVB | Agglo Sud Volley Ball |
| ASW | All Star Wrestling |
| AT | Agent Team |
| AT | All Times |
| AT | Arranged Team |
| ATA | American Taekwondo Association |
| ATB | All Terrain Bicycle |
| ATB | All Terrain Boarding aka mountain boarding |
| ATB | All-Terrain Bike |
| ATC | Achilles Track Club |
| ATC | Against The Clock |
| ATC | Archery Training Class |
| ATC | Athletic Training and Conditioning |
| ATCC | Avenir Triathlon Club Charleroi |
| ATD | Automatic Take Down |
| ATH | Arm The Homeless |
| athl | athlete |
| athl | athletics |