Where does “tri deg un” come from?

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

tri deg un (Welsh): thirty-one

Definitions

  1. thirty-one

Ancestry of “tri deg un”, step by step

tri deg un traces back through 3 separate lines of ancestry.

via Welsh un

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

via Welsh tri

StepLanguageWordMeaning
1Welshtrithree
2Proto-Brythonictrithree
3Proto-Celtictrīsthree
4Proto-Indo-European*tréyes

via Welsh deg

StepLanguageWordMeaning
1Welshdegten; Soft mutation of teg
2Proto-Brythonicdegten
3Proto-Celticdekamten
4Proto-Indo-Europeandéḱm̥ten
Every word from Proto-Indo-European óynos