| Abbreviation | Definition |
|---|---|
| AORS | Ocean Race Series |
| APAP | acetyl para aminophenol and paracetamol |
| APR | Arizona Pylon Racing |
| APR | Audi Performance and Racing |
| APRA | Arizona Pylon Racing Association |
| APRA | Australian Pulsar Racing Association |
| AR | Adventure Racing |
| ARABS | American Registry of Arab Bred Sporthorses |
| ARAC | All Races All Classes |
| ARB | Australian Racing Board |
| ARC | Active Race Control |
| ARC | Adventure Racing Canada |
| ARC | Alloy Racing Composites |
| ARC | Atlantic Rally for Cruisers |
| ARCA | Amateur racers crashers association |
| ARCA | Automobile Race Car Association |
| ARCA | Automobile Racing Club of America |
| ARCI | Association of Racing Commissioners International |
| ARDC | American Racing Drivers Club |
| ARF | Amazing Race Fan |