Where does “-eu” come from?

-eu (Middle Welsh) comes from Old Welsh -ou, from Proto-Brythonic -ow, from Proto-Celtic -owes.

Ancestry of “-eu”, step by step

StepLanguageWordMeaning
1Old Welsh-ou—
2Proto-Brythonic-ow—
3Proto-Celtic-owes—

Words derived from “-eu”

Every word from Proto-Celtic -owes →Every word from Proto-Brythonic -ow →Every word from Old Welsh -ou →