Ó Cróinín
Ó CRÓINÍN—I—O Cronine, O Cronyn, Cronin, Cronyn, Cronan; 'descendant of Cróinín' (diminutive of crón, brown, swarthy); the name of a family of Corca Laoighdhe, originally seated in the neighbourhood of Clonakilty, but now numerous throughout Cork, Kerry and Limerick.
Alphabetical Index to Irish Surnames