| Abbreviation | Definition |
|---|---|
| CPOC | Chrysler Product Owners Club |
| CPSA | Cuban Philatelic Society of America |
| CPU | Cutting Papers Upward |
| CRAP | Citizens Raging Against Phones |
| CRC | Customs, Rods, and Classics |
| CRCA | California Rock Crawlers Association |
| CRCC | Creative Retirement Computer Club |
| CRES | Cheshire Reptile Enthusiasts Society |
| CRM | Can't Remember Much |
| CROCC | Columbia River Outrigger Canoe Club |
| CRV | Cute Runabout Vehicle |
| CS | Club Stamp |
| CSAC | Citizens Stamp Advisory Committee |
| CSAC | Clan Sinclair Association Canada |
| CSAF | Confederate States Air Force |
| CSAF | Cross Stitch Anatomy Fans |
| CSC | Celtic Supporters Club |
| CSC | Cosmic Sewing Circle |
| CSRA | Canadian Street Rod Association |
| CSUK | Christian Surfers United Kingdom |