Where does “ad” come from?

ad (Old Welsh) comes from Proto-Celtic ad, from Proto-Celtic *tāyeti, from Proto-Indo-European *steh₂-.

Ancestry of “ad”, step by step

StepLanguageWordMeaning
1Proto-Celticadto
2Proto-Celtic*tāyetito stand
3Proto-Indo-European*steh₂-—

Words derived from “ad”

Every word from Proto-Indo-European *steh₂- →Every word from Proto-Celtic *tāyeti →Every word from Proto-Celtic ad →