Ó Dearáin
Ó DEARÁIN—I—O Dearain, O Derane, Dearan, Derrane, Dirrane; 'descendant of Dearán' (diminutive of dear, great, large); a rare and scattered surname; found chiefly in the 16th century, in Kildare, Leix and Galway. MacFirbis mentions a Muinntear Dearain among the Cinel Eoghain, in Ulster.
Alphabetical Index to Irish Surnames