Where does “ungorn” come from?

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

Ancestry of “ungorn”, step by step

ungorn traces back through two separate lines of ancestry.

via Welsh un

StepLanguageWordMeaning
1Welshunonly; one; one, individual
2Middle Welshunone
3Proto-Brythonicʉnone
4Proto-Celticoinosone
5Proto-Indo-Europeanóynosone; single

via Welsh corn

StepLanguageWordMeaning
1Welshcornhorn; chimney
2Middle Welshcornhorn
Every word from Proto-Indo-European óynos →