Ó Doirnáin is an Irish Gaelic surname that serves as the original Irish form of the anglicized surname Durnin. The name originates from the Gaelic Ó Doirnáin, meaning "descendant of Doirnín," where Doirnín is a personal name derived from dorn meaning "fist" combined with a diminutive suffix, literally translating to "little fist." This etymology likely referred to a person with a small or clenched fist, or perhaps metaphorically to a striker or fighter. The surname is primarily associated with Ireland and reflects a common Gaelic patronymic naming tradition. While the name has spread to other English-speaking countries through emigration, its historical and cultural roots remain deeply tied to Irish heritage. Distribution data from surname resources show the name appearing in relatively small numbers today, with most bearers found in Ireland and regions with significant Irish diaspora populations. Historical ContextLike many Irish surnames, Ó Doirnáin underwent anglicization during the 16th to 19th centuries, often losing the O' prefix or being restructured to conform to English phonetics. The anglicized form Durnin became more common in administrative records, though the original Gaelic form persists within Irish-speaking communities and among those emphasizing ancestral identity. Meaning: Descendant of Doirnín ("little fist") Origin: Irish Gaelic Type: Patronymic surname Usage Regions: Ireland, United Kingdom, United States, Canada, Australia