| Abbreviation | Definition |
|---|---|
| CKR | Cycle King Racing |
| CMR | Carnegie Mellon Racing |
| CMRA | Central Motorcycle Roadracing Association |
| CMRC | Canadian Motorsport Racing Club |
| CMRC | Canadian Motosport Racing Corp |
| CMRE | Coy Miller Race Engines |
| COAR | Central Ohio Adventure Racing |
| COCP | Combined Oral Contraceptive Pill |
| CORA | Charleston Ocean Racing Association |
| CORC | Central Ohio Rally Club |
| CORE | Capitol Off Road Enthusiasts |
| CORR | Championship Off-Road Racing |
| CORS | Central Ontario Racing Series |
| CORT | Caribbean Ocean Racing Triangle |
| CPTC | Cedar Park Track Club |
| CPTC | Central Park Triathlon Club |
| CPTP | completely positive trace preserving |
| CPTR | Center for Physical Trace Research |
| CPTR | CENTRE For PHYSICAL TRACE RESEARCH |
| CQRL | Conseil Québécois des races laitières |