Ó Duibhghiolla
Ó DUIBHGHIOLLA—I—Duffley, Diffily, Diffely, Diffley, Deffely, Divilly, Devilly, Devily, Deely, Dealy, &c.; 'descendant of Dubhghiolla' (black-lad); the name (1) of a family of the southern Ui Fiachrach, who were chiefs of Cinel Cinnghamhna, near Kinvara, in south-west of Co. Galway; and (2) of a family of Siol Anmchadha, in the south-east of the same county.
Alphabetical Index to Irish Surnames