Calihan

Calihan is an anglicized form of the Irish surname Ó Ceallacháin. The surname itself is derived from the given name Ceallachán, which means 'lover of churches' or 'frequenter of churches,' from 'ceallach' (church) and the diminutive suffix '-án'. The Ó Ceallacháin clan was a powerful sept in County Cork, Ireland, particularly prominent in the barony of Duhallow. They were chieftains of the Uí Eathach Mhumhan, a Munster tribe.

Over centuries, as Irish names were anglicized, Ó Ceallacháin became Callahan, Callaghan, and Calihan. While primarily a surname, Calihan has occasionally been adopted as a given name, especially in areas with a strong Irish diaspora. Its use as a first name is relatively uncommon but growing, often chosen for its distinctive sound and Irish heritage.