Ó Duibh
Ó DUIBH—I—O Duff, O'Diff, Duff, and, by translation, Black; 'descendant of Dubh' (Black); the name of an old family in Leix who were chiefs of Cinel Criomhthainn, in the present barony of East Maryborough; also apparently of a Connacht family.
Alphabetical Index to Irish Surnames