| Name | Gender | Pronounced | Usage | Popularity |
|---|---|---|---|---|
| Cornelius | kər-NEE-lee-əs (English), kawr-NAY-lee-us (Dutch), kawr-NE-lee-uws (German) | Ancient Roman, English, Dutch, German, Biblical | ||
| CorraidhÍN | - | Ancient Irish | ||
| Cosmas | - | Ancient Greek (Latinized) | ||
| Crispinus | - | Ancient Roman | ||
| Crispus | - | Ancient Roman | ||
| Cuidightheach | - | Ancient Irish | ||
| Cunigund | - | Ancient Germanic | ||
| Cunobelinus | kyoo-no-bə-LIEN-əs (English) | Ancient Celtic | ||
| Cynbel | - | Ancient Celtic | ||
| Cynwrig | - | Ancient Celtic | ||
| Cyprianus | - | Ancient Roman | ||
| Cyrillus | - | Ancient Greek (Latinized) | ||
| Cyrus | SIE-rəs (English) | English, Biblical, Biblical Latin, Ancient Greek (Latinized) | ||
| Dagfinnr | - | Ancient Scandinavian | ||
| Dagm&Aelig;R | - | Ancient Scandinavian |