Where does “trydanllyd” come from?

trydanllyd (Welsh) comes from Welsh trydan, from Welsh tân, from Middle Welsh tan, from Proto-Brythonic tan, from Proto-Celtic teɸnets, from Proto-Indo-European tep- — to be warm, be hot.

Ancestry of “trydanllyd”, step by step

StepLanguageWordMeaning
1Welshtrydanelectricity; electric fluid
2Welshtânfire
3Middle Welshtan—
4Proto-Brythonictanunder; fire
5Proto-Celticteɸnetsfire
6Proto-Indo-Europeantep-to be warm, be hot
Every word from Proto-Indo-European tep- →Every word from Proto-Celtic teɸnets →Every word from Proto-Brythonic tan →