“Brett” - gender neutral Celtic Name meaning “from Breton.” Or from “Brittany, as Brittany was one of the original Six Celtic Nations along with Ireland, Scotland, Cornwall, Wales, Isle of Man.
“Brittany” is the geographic location, on the Atlantic coast of France. “Breton” is the ethno-linguistic group (Celtic family) originally found there.
Isle of Man?
That’s sexist!
Rename: Isle of Zir.