Dóru + weyd – Proto Indo European
Dru + wid – Proto Celtic
Druwits – Proto Celtic
Druits/Druið – Gaulish
The modern term Druid comes from the Latin druidēs (plural) ancient Roman writers considered it a native word from Gaul. The earliest term is from Greek Δρυΐδαι (druidai) (plural). Other texts use the form druidae.
Linguists still do not agree on the meaning of Druidae but they do agree that it is of Gaulish origins. There are many theories of where the word Druidae comes from, here are a few: Pliny the Elder and Strabo both think that it was a cognate of a Greek word meaning an ‘Oak’ (Drus).
Mrs. Chadwick suggests it could have originated in a nickname derived from the oak forests – which Pliny associated with them, so the word could mean something like ‘Backwoodsmen’.Other leading etymologists seem to think the word derives from the root words
Dru – Meaning Oak Knowledge
Wid – Meaning ‘to Know – to see’ (like vid in the Vedas)
A close meaning of the word Druid:
‘Those whose Knowledge is Great’
We also have the Gaulish Compound
Dru-, Drus, the world tree.
Uits, Uid, know.
“One who knows the world tree”