Ó Cormacáin
Ó CORMACÁIN—I—O Cormacan, O Cormakane, O Gormacan, Cormocan, Cormican, Gormican, (Cormack, Cormick, MacCormack, MacCormick); 'descendant of Cormacán' (diminutive of Cormac); the name of at least four distinct families in different parts of Ireland, viz.: (1) Ó Cormacáin of Roscommon. This family appears to have been connected with the church of St. Coman. Fionn O Cormacain was one of the four hostages given by Cahal Crovderg O'Conor, King of Connacht, to King John, when the latter visited Ireland in 1210. (2) Ó Cormacáin of Thomond, a branch of the Dal gCais. These appear to have been an ecclesiastical family and erenaghs of the parish of Moynoe, in Co. Clare. Three of them were bishops of Killaloe in the 13th and 14th century. (3) Ó Cormacáin of Galway, a family formerly seated in the parish of Abbey-Gormican, in the barony of Longford, where they founded the abbey from which the parish derives its name. (4) Ó Cormacáin of Down, an ecclesiastical family who were erenaghs of Iniscourcey. The name appears to have been sometimes corrupted to Ó Gormacáin, was often shortened to Ó Cormaic (which see), and is now in many places disguised under the anglicised form of MacCormack.
Alphabetical Index to Irish Surnames