| Cloee | A diminutive form of Cloe, derived from Chloe, meaning 'blooming' or 'green shoot'. |
| Clovis | Famous warrior in battle. |
| Clyff | Diminutive of Clifford: River ford near a cliff. |
| Cnute | A variant of the name Canute. |
| Cobb | Variant of Cob: Heel. |
| Cobhan | Dwells by the hillside hollow. |
| Coira | A name meaning from the cauldron. |
| CoireaIl | A name meaning a deep whirlpool. |
| Cola | A name meaning a charcoal person. |
| Coleta | A victorious young woman. |
| Coligny | From the forest of Colius. |
| Collton | Variant of Colton: From a dark town. Also a variant of Colston: Unknown owner of property. |
| Colman | A name meaning a little dove. |
| Colmcille | Dove of the church |
| Colston | Unknown owner of property. |
| COLUM | Derived from the Latin for dove. |
| Columbina | Feminine form of Columba: Dove. Famous bearer: 6th century Irish abbot and missionary St Columba converted the inhabitants of Scotland and northern England to Christianity. |
| Columbo | Derived from the Latin columba |
| Com | A shortened form of community |
| Concetta | Reference to the Immaculate Conception |
| Conleth | Means pure or holy fire in Gaelic. |
| Connlaio | A name meaning a pure, holy one. |
| Connlaoi | Variant of Connlaodh: Pure fire. |
| Constancy | A variant of Constance used by 16th and 17th century Puritans. |
| Constant | Variant of Constantine: Steady; stable. |
| Constanzie | Constancy; steadfastness. |
| Conway | Hound of the plain |
| Cooey | Hound of the plains |
| Cooper | An occupational name for a barrel maker. |
| Coowescoowe | Cherokee name meaning egret. |
| Coralina | From the coral of the sea. |
| Corann | A name meaning maiden or spear bearer. |
| Corazon | A Spanish name meaning the human heart. |
| Corbet | A name meaning a little dark raven. |
| Corbitt | Raven. Variant of Corbet: Black-haired. |
| Coreene | A variant meaning young girl. |
| Coridan | Ready to fight. |
| Corine | Derived from corinne |
| CORINEUS | A legendary Trojan warrior. |
| Corney | Diminutive of Cornelius: Strong willed or wise. Cornelius is sometimes used as a translation of the name Conchubhar meaning High Desire. |