O'Brien
A famous Irish surname meaning “descendant of Brian,” ultimately tied to the personal name Brian.
The #258 most common surname in the United States (2010 Census) — about 1 in every 2,604 Americans shares it.
Etymology
O'Brien is the anglicized form of the Irish surname Ó Briain. The prefix Ó means “descendant of,” and Brian is an old personal name whose exact original sense is uncertain, though it is often associated with ideas of nobility or high status in later tradition. In plain terms, the surname means “descendant of Brian.”
History
The O'Briens were one of the great ruling families of Ireland, especially linked with Munster and the medieval kingship of Thomond. The surname spread widely through Irish migration and is now common in Ireland, Britain, North America, and other English-speaking countries. Historical spelling often varies, and forms without the apostrophe are common in modern records.
Origin
Regions
Variant spellings
Fun fact
The O'Brien dynasty is one of the best-known Gaelic noble families, and the name appears in many Irish place-names and historical pedigrees.
From the historical record
“iersche geslachtsnamen meer in Vlaanderen en Brabant als in Holland worden aangetroffen. Zie hier de weinigen, die my zijn voorgekomen: Obreen met de byformen Obrien, ook O' Brie n geschreven, en O brie; Ogilvie (te Batavia), O 'Kelly en 0'Toole,Sheridan en Sullivan. Den geslachtsnaam C a r m i g- gelt, ongetwyfeld…”
— De Nederlandsche geslachtsnamen in oorsprong, geschiedenis en beteekenis