| Abbreviation | Definition |
|---|---|
| CKO | Club Knock Out |
| CKSC | Central Kentucky Soccer Club |
| CKSC | Central Kitsap Soccer Club |
| CKSC | Central Kitsap Soccer Club's |
| CL | Club Letter |
| CLCC | Capital Land Cruiser Club |
| CLCC | Columbine Lake Country Club |
| CLCC | Cranberry Lake Community Club |
| CLF | Club Lotus France |
| CLNT | Club des Loisirs Nautiques Thalassa |
| CLPC | Charleston Lake Pony Club |
| CLRC | Cape Land Rover Club |
| CLRC | Christian Legal Reformation Club |
| CLRI | Club Land Rover Ireland |
| CLWAC | Catharine Lorillard Wolfe Art Club (New York, NY) |
| CLWC | Central London Wargames Club |
| CMAA | Club Managers' Association Australia |
| CMAA | Club Managers Association of America |
| CMAC | Columbia Marine Aquarium Club |
| CMAC | Corsair Model Aircraft Club |