Where does “rhagluniau” come from?

rhagluniau (Welsh) comes from Welsh Iau, from Middle Welsh ieu, from Brythonic *Yow, from Latin Iovem, from Proto-Indo-European dyew- — to be bright; sky, heaven.

Ancestry of “rhagluniau”, step by step

rhagluniau traces back through two separate lines of ancestry.

via Welsh Iau

StepLanguageWordMeaning
1WelshIauJupiter, Thursday
2Middle Welshieu—
3Brythonic*Yow—
4LatinIovem—
5Proto-Indo-Europeandyew-to be bright; sky, heaven

via Welsh rhaglun

StepLanguageWordMeaning
1Welshrhaglunpreview
2Welshllunshape, figure, form; picture, drawing,...
Every word from Proto-Indo-European dyew- →Every word from Latin Iovem →Every word from Brythonic *Yow →