ONeil

ONeil is a surname variant derived from the Irish Ó Néill, meaning “descendant of Niall.” The name belongs to one of the principal Gaelic dynasties of medieval Ireland, the Uí Néill, which played a prominent role in Irish history. The given name Niall is often connected with the figures Niall of the Nine Hostages and is widely interpreted as meaning “champion” or “cloud.” Over time, Ó Néill gave rise to numerous Anglicized spellings.

In modern use, the surname has many spellings and forms, including O'Neill, O'Neil, Oneill, Oneal, and O'Neal. The unpunctuated variant ONeil is a common occurrence in records, databases, and branding, while O'Neill and related forms remain the most widely recognized in Irish and American contexts. The name is found throughout Ireland and has spread to the United States, Canada, the United Kingdom, Australia, and other regions through Irish and wider diaspora migration.

Usage notes: ONeil and its variants are used as both a surname and, less commonly, as a given name in some instances. The exact spelling often reflects historical period, regional preferences, or personal choice in modern times.

Notable individuals: One of the best-known bearers of a closely related form is Eugene O'Neill (1888–1953), an American dramatist who won the Nobel Prize in Literature in 1936. Beyond O'Neill, the Ó Néill lineage and its descendants appear in various fields—arts, politics, and sports—across the Irish diaspora, illustrating the name’s long-standing cultural and geographic reach.