| Custodia | Woman | Spanish Names |
| Cuthbert | Man | English Names |
| Cutler | Man | English Names |
| Cutter | Man | English Names |
| Cuyler | Man | Dutch Names |
| Cwen | Woman | English Names |
| Cy | Man | Greek Names |
| Cyan | Unisex | American Names |
| Cyanne | Woman | English Names |
| Cybele | Woman | Greek - Phrygian Names |
| Cybil | Woman | Greek Names |
| Cybille | Woman | French Names |
| Cyd | Unisex | Greek Names |
| Cyma | Woman | Greek Names |
| Cynara | Woman | Greek Names |
| Cyndi | Woman | Greek Names |
| Cyneburg | Man | English Names |
| Cynna | Woman | American Names |
| Cynthia | Woman | Greek Names |
| Cynzia | Woman | Italian Names |