Brennan (surname)

Brennan (/ˈbrɛnən/)^[1] is an Irish surname which is an anglicised form of two different Irish-language surnames: Ó Braonáin and Ó Branáin (or Mac Branáin).^[2][3][4] Historically, one source of the surname was the prominent clan Ua Braonáin (O'Brennan) of Uí Duach (Idough)^[5] in Osraige who were a junior Dál Birn sept stemming from a younger son of Cerball mac Dúnlainge (d.888).^[6] Recent surname evaluations highlighted the geographic consistency of this lineage in the barony of Idough.^[7][8] However, based on the ultimate authority of Dubhaltach Mac Fhirbhisigh they are out of Ui Dhuinn (O’Dunn)^[9] and, therefore, an Uí Failghi tribe, not Osraige. While it is clearly apparent that O’Hart's pedigree is erroneous, it is suggested that Ó Cléirigh probably became confused while transcribing from Mac Fhirbhisigh.^[10] This is echoed by the modern scholar, Bart Jaski.^[11]

The Irish surname Ó Braonáin, means "descendant of Braonán". The personal name Braonán is derived from a word which means "moisture", "drop". The Irish surname Ó Branáin, means "descendant of Branán". The personal name Branán means "little raven".^[12] Brennan is also a given name.

Notable people with the surname include: