The story
- Old Irish · derived frombrithem
- Irish · derived frombreitheamh
- English todaybrehon
From an Anglicized oblique form (such as genitive singular breitheamhan or dative singular breitheamhain) of Irish breitheamh, from Old Irish brithem, from breth (“judgment”).
Etymology from Wiktionary, CC BY-SA 4.0.