| Abbreviation | Definition |
|---|---|
| BYOW | Bring Your Own Weapon |
| BYR | Bring Your Reefers |
| BYS | Birmingham Youth Soccer |
| BYS | Bluffton Youth Sports |
| BYS | Brunswick Youth Sports |
| C | Catcher (baseball) |
| C | Center |
| C | Challenger |
| C | Championship |
| C | Cleverness factor |
| C | Club |
| C | Coach |
| C | Crowned |
| C | Cubs |
| C&DCL | Calgary and District Cricket League |
| CAA | Carrollton Athletic Association |
| CAA | Certified Athletic Administrator |
| CAA | Connecticut Archery Association |
| CAAC | Capital Area Activities Conference |
| CAAC | Columbus Area Aquatic Center |