Ó Cuacháin
Ó CUACHÁIN—I—O Coughane, O Cowghane, O Quoghane, (Gough); 'descendant of Cuachán' (diminutive of cuach, a cuckoo); the name of a family of Ui Fiachrach, formerly seated in the barony of Carra, Co. Mayo, where O'Donovan found it still extant under the anglicised form of Gough. At the end of the 16th century, it appears in Roscommon, Cavan and Cork, but I have failed to discover any modern anglicised form of it in these counties.
Alphabetical Index to Irish Surnames