| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 241 | Crist | Welsh | Christian. | M | |
| 242 | Cubert | Welsh | Legendary son of Daere. | M | |
| 243 | Culhwch | Welsh | Legendary son of K;Iydd. | M | |
| 244 | Culvanawd | Welsh | Legendary son of GwIyon. | M | |
| 245 | Custenhin | Welsh | Legendary father of Erbin. | M | |
| 246 | Cwrig | Welsh | Master. | M | |
| 247 | Cymreiges | Welsh | Welsh woman. | F | |
| 248 | Cymry | Welsh | From Wales. | M | |
| 249 | Cynan | Welsh | Chief. | M | |
| 250 | Cynbal | Welsh | Warrior chief. | M | |
| 251 | Cynbel | Welsh | Warrior chief. | M | |
| 252 | Cynddelw | Welsh | Chief statue. | M | |
| 253 | Cyndeyrn | Welsh | Head chief. | M | |
| 254 | Cystenian | Welsh | Steady; stable. | M | |
| 255 | Cystennin | Welsh | Constant. | M | |
| 256 | Daere | Welsh | Fiend. | F | |
| 257 | Dafydd | Welsh | A Welsh form of the Hebrew name David, meaning beloved or friend. | M | |
| 258 | Dai | Welsh | Shines. A Welsh diminutive of David, meaning beloved or friend.. | M | |
| 259 | Dal | Welsh | Diminutive of David: Beloved or friend, from the Hebrew. Sixth century St David (or Dewi) was patron saint of Wales. | M | |
| 260 | Dalldav | Welsh | Legendary son of Cunyn Cov. | M | |