Where does “umpryt” come from?

umpryt (Middle Welsh) comes from Middle Welsh un, from Proto-Brythonic ʉn, from Proto-Celtic oinos, from Proto-Indo-European óynos — one; single.

Ancestry of “umpryt”, step by step

StepLanguageWordMeaning
1Middle Welshunone
2Proto-Brythonicʉnone
3Proto-Celticoinosone
4Proto-Indo-Europeanóynosone; single
Every word from Proto-Indo-European óynos →Every word from Proto-Celtic oinos →Every word from Proto-Brythonic ʉn →