Where does “Dydd Gŵyl Dewi” come from?

Dydd Gŵyl Dewi (Welsh) comes from Welsh dydd, from Middle Welsh dyð, from Old Welsh did, from Proto-Brythonic dið, from Proto-Celtic dīyos, from Proto-Indo-European dyḗws, from Proto-Indo-European dyéws, from Proto-Indo-European dyew- — to be bright; sky, heaven.

Dydd Gŵyl Dewi (Welsh): Saint David's Day Welsh national day

Definitions

  1. Saint David's Day Welsh national day

Ancestry of “Dydd Gŵyl Dewi”, step by step

Dydd Gŵyl Dewi traces back through 3 separate lines of ancestry.

via Welsh dydd

StepLanguageWordMeaning
1Welshdyddday, daytime
2Middle Welshdyðday
3Old Welshdidday
4Proto-Brythonicdiðday, daytime
5Proto-Celticdīyosday
6Proto-Indo-Europeandyḗwssky, heaven; sky god
7Proto-Indo-Europeandyéwssky, heaven
8Proto-Indo-Europeandyew-to be bright; sky, heaven

via Welsh gŵyl

StepLanguageWordMeaning
1Welshgŵylvigil; holiday, festival, feast; holiday,...
2Middle Welshgŵyl
3Proto-Celtic*weilosmodest
4Proto-Indo-Europeanwéy-
5Proto-Indo-Europeanéǵh₂I

via Welsh dewi

StepLanguageWordMeaning
1WelshdewiSoft mutation of tewi
Every word from Proto-Indo-European dyew-Every word from Proto-Indo-European dyéwsEvery word from Proto-Indo-European dyḗws