Where does “nos Iau” come from?

nos Iau (Welsh) comes from Welsh nos, from Middle Welsh nos, from Latin nox, from Proto-Italic nokts, from Proto-Indo-European nókʷts, from Proto-Indo-European negʷ- — bare, naked.

nos Iau (Welsh): Thursday night

Definitions

  1. Thursday night

Ancestry of “nos Iau”, step by step

nos Iau traces back through two separate lines of ancestry.

via Welsh nos

StepLanguageWordMeaning
1Welshnosnight
2Middle Welshnos—
3Latinnoxnight; darkness; a dream
4Proto-Italicnoktsnight
5Proto-Indo-Europeannókʷtsnight
6Proto-Indo-Europeannegʷ-bare, naked

via Welsh Iau

StepLanguageWordMeaning
1WelshIauJupiter, Thursday
2Middle Welshieu—
3Brythonic*Yow—
4LatinIovem—
5Proto-Indo-Europeandyew-to be bright; sky, heaven
Every word from Proto-Indo-European negʷ- →Every word from Proto-Indo-European nókʷts →Every word from Proto-Italic nokts →