| Abbreviation | Definition |
|---|---|
| CMRC | Cleveland Model Railway Club |
| CMRC | Crossville Model Railroad Club |
| CMSC | Ceylon Motor Sports Club |
| CMSO | Club Municipal Sportif Oissel |
| CMYC | Cedar Mills Yacht Club |
| CMYC | Christchurch Model Yacht Club |
| CN | Club Number |
| CNAC | Central Nebraska Auto Club |
| CNBA | Club de Natation de Ben Arous |
| CNBF | Club de natation des Bois Francs |
| CNBI | Club Nautique de Berthier Inc |
| CNCC | Central Northern Coalition of Clubs |
| CNDR | Club de Natation les Dauphins de Rimouski |
| CNFT | Club Nautique Fran??ais de Tegel |
| CNFT | Club Nautique Français de Tegel |
| CNIP | Club Nautique Ile Perrot |
| CNLC | Conroe Noon Lions Club |
| CNMA | Club de Natation de Maisons Alfort |
| CNMB | Club Nautique Mons Borinage |
| CNOC | Chicago Norton Owners Club |