Ó Comhdhain
Ó COMHDHAIN—I—O Coain, O Coan, O Cowan, Coan, Coen, Cowan, Cowen, (Coyne), &c.; 'descendant of Comhghan' (co-birth); also written Ó Comhghain; the name of a branch of the Ui Fiachrach, anciently seated in the parish of Dunfeeny, Co. Sligo, but in the 16th century more numerous in Galway and Roscommon. The name is still well known in Connacht, usually anglicised Coen.
Alphabetical Index to Irish Surnames