Ó Deóradháin
Ó DEÓRADHÁIN, Ó DEÓRAIDHÍN, Ó DEÓRÁIN—I—O Dorian, O Dowerine, O Doreane, O Dorrane, Adorian, O'Doran, Dorian, Dorrian, Doran, Dorran, Durrian; 'descendant of Deóradhán' or 'Deóraidhín' (diminutive of deóradh, an exile, stranger); the name (1) of a great brehon family in Leinster, where it is still very common; and (2) a Co. Down surname. Ó Deoráin is a shortened form of Ó Deóradháin; Ó Deóraidhín was everywhere a variant.
Alphabetical Index to Irish Surnames