Where does “chwyddiannau” come from?

chwyddiannau (Welsh) comes from Welsh chwyddiant, from Welsh chwyddo, from Welsh chwydd, from Middle Welsh chwyd, from Proto-Brythonic hwuɨð, from Proto-Celtic swēdus.

Ancestry of “chwyddiannau”, step by step

StepLanguageWordMeaning
1Welshchwyddiantinflation, distension, increase
2Welshchwyddoto swell, to inflate
3Welshchwyddswelling
4Middle Welshchwyd—
5Proto-Brythonichwuɨðswelling
6Proto-Celticswēdus—
Every word from Proto-Celtic swēdus →Every word from Proto-Brythonic hwuɨð →Every word from Middle Welsh chwyd →