druid

Borrowed from French druide, from Old French, via Latin Druidae, from Gaulish *druwits, from Proto-Celtic *druwits (literally either “oak-knower” or “firm knower, great sage”), from either Proto-Indo-European *dóru (“tree”) or *drew- (“solid, firm, hard”) and *weyd- (“to see, to have knowledge”) (whence also English wizard; Proto-Slavic *vědьma (> Russian ве́дьма (védʹma))).

The earliest record of the term in Latin is by Julius Caesar in the first century B.C. in his De Bello Gallico. The native Celtic word for "druid" is first attested in Latin texts as druides (plural) and other texts also employ the form druidae (akin to the Greek form). Cognate with the later insular Celtic words, Old Irish druí (“druid, sorcerer”) and early Welsh dryw (“seer”).