Breannon is a name of Irish origin, derived from the Irish surname Ó Braonáin, which means 'descendant of Branán'. It is typically anglicized as Brennan and can also be found in its Gaelic form, O'Braonáin. In Irish mythology, Brehon law refers to the legal system that governed Ireland before British rule.
"The name Breannon peaked in popularity during the late 1980s to mid-1990s with consistent usage over the years."