| Abbreviation | Definition |
|---|---|
| CKA | Chinese Karate Association |
| CKA | Colorado Karate Association |
| CKBC | Crazy Kouzu Basketball Club |
| CKD | Choi Kwang Do |
| CKD | Completely Knocked Down |
| CKSC | California Kids Sports Center |
| CL | Champions League |
| CLE | Cleveland Indians |
| CLEAR | Canadian Loss Experience Automobile Rating |
| CLEC | Carlingford Lough Endurance Challange |
| CLIC | Cycle Lab Information Center |
| CLQ | Champions League for Quake |
| CLRA | Carnegie Lake Rowing Association |
| CM | Central Midfielder |
| CMA | Carolina Marathon Association |
| CMAA | Canadian Masters Athletic Association |
| CMAA | Cobra Martial Arts Association |
| CMAF | Canadian Martial Arts Federation |
| CMAF | Championship Martial Arts Foundation |
| CMAF | Christian Karate and Martial Arts of Michigan |