| Abbreviation | Definition |
|---|---|
| COHC | City of Oxford Hockey Club |
| COHM | Club Olympique De La Haute Moselotte |
| COI | Colors of India |
| COLYC | Columbia Yacht Club (Chicago, Illinois) |
| COMRC | Central Ohio Model Railroad Club |
| CONC | Central Okanagan Naturalists Club |
| CONC | Central Oregon Nordic Club |
| COOC | Cambridge Oxford Owners Club |
| CORC | Central Ohio Rally Club |
| CORC | Clubcanberra Ocean Racing Club |
| COSCA | Central Ohio Saddle Club Association |
| COTC | Central Ohio Triathlon Club |
| COTC | Central Oregon Track Club |
| COVC | Classic Oldtimer Veteranen Club |
| COWC | Council Oak Woodcarvers Club |
| CPA | Club Posh Artistic |
| CPAB | Club de patinage artistique de Boucherville |
| CPAC | Cal Poly Accounting Club |
| CPAC | College Park Aquatic Club |
| CPAV | Club de patinage artistique de Valleyfield |