Where does “úaill” come from?

úaill (Old Irish) comes from Proto-Celtic ouxslā, from Proto-Celtic ouxselos, from Proto-Indo-European h₃ewps-.

Ancestry of “úaill”, step by step

StepLanguageWordMeaning
1Proto-Celticouxslā—
2Proto-Celticouxseloshigh, elevated
3Proto-Indo-Europeanh₃ewps-—
Every word from Proto-Indo-European h₃ewps- →Every word from Proto-Celtic ouxselos →Every word from Proto-Celtic ouxslā →