From Ó Braonáin, most likely ‘moist’ or ‘sorrowful’ — distinct septs in Kilkenny and Roscommon carried the name.
Gaelic Origin · Root name Braonán
Brennan descends from Braonán, built on braon (‘moisture’ or ‘teardrop’); readings range from ‘sorrowful’ to simply a personal name in its own right. Unrelated Ó Braonáin septs held ground in both Kilkenny and Roscommon, which is part of why the name is common across such different parts of Ireland.
A name whose meaning is gentle even where its history wasn't — two separate Gaelic families, hundreds of miles apart, choosing the same word for their own.
Irish form: Ó Braonáin
