Welsh word cei comes from Proto-Celtic *kagyom (Pen, enclosure.), Latin coacto (I compel, constrain, force.)
| Dictionary entry | Language | Definition |
|---|---|---|
| *kagyom | Proto-Celtic (cel-pro) | Pen, enclosure. |
| coacto | Latin (lat) | I compel, constrain, force. |
| cagiíun | Gaulish (cel-gau) | |
| cagiíum | Gaulish (cel-gau) | |
| *kagyom | Gaulish (cel-gau) | |
| coagulum | Latin (lat) | Curd. Rennet. Thickening, congealing. Tie, bond, binding agent. |
| caium | Latin (lat) | (Middle Latin) quay, wharf. (Middle Latin) storehouse, shop, workshop. |
| cail | Old French (fro) | Quay; wharf. |
| key, keye | Middle English (enm) | |
| cei | Welsh (cym) | Quay. |