What is Brehon?

Legal Definition
Brehon (Irish: breitheamh - IPA brʑehəvɤ or brʑejuː) is a term for a historical arbitration, mediative and judicial role in Gaelic culture. Brehons were part of the system of Early Irish law, which was also simply called "Brehon law".
-- Wikipedia
Legal Definition
In old Irish law. A judge. 1 Bl. Comin. 100. Brehons, (breitheamhuin,) judges.
-- Black's Law Dictionary
Legal Definition
(Irish) An hereditary judge.
-- Ballentine's Law Dictionary