Where does “coil(i)ou” come from?

coil(i)ou (Old Welsh) comes from Proto-Brythonic koïl, from Proto-Celtic kailo-, from Proto-Indo-European kóylos — healthy, whole; safe, unharmed.

Ancestry of “coil(i)ou”, step by step

StepLanguageWordMeaning
1Proto-Brythonickoïlomen, augury
2Proto-Celtickailo-—
3Proto-Indo-Europeankóyloshealthy, whole; safe, unharmed

Words derived from “coil(i)ou”

Every word from Proto-Indo-European kóylos →Every word from Proto-Celtic kailo- →Every word from Proto-Brythonic koïl →