| Abbreviation | Definition |
|---|---|
| CATH | Catherine |
| CATREEN | Courageous, Adorable, Toleranced, Reliant, Eloquent speaker, Everlasting lover, Nourisher |
| CB | Charley Boy |
| CB | Connor Berry |
| CC | Calendar Cat |
| CC | Christmas Cat |
| CC | Connie Cockatiel |
| CCC | Chaos Computer Club |
| CCH | Carol Christine Hilaria Pounder |
| CCW | Colton Christopher Wilson |
| CD | Cyber Dad |
| Celeb | Celebrity |
| CG | Charles George |
| CG | Christian Gail |
| CH | Christian Hartmann |
| CHARPHIE | Charlotte + Sophie = CHARPHIE |
| ChemTech | Chemical Technician |
| CHY | Chowdhury |
| CJ | Caesar Joseph |
| CJ | Caitlin Jade |