The surname in Irish is O Croinin, from a diminutive of cron, meaning "yellow" or "swarthy. A more accurate rendition of the original pronunciation would be "Croneen", and this survives in placenames embodying the name - Cooscronin ("Cronin's hollow") and Liscroneen ("Cronin's fort") in west Cork, and Ballycroneen in Imokilly barony in east Cork. As the placenames imply, the origin of the family lies in Cork, in particular in the west of the county, where they were originally part of the Corca Laoighdhe. In the Gaelic genealogies of this tribal grouping, the Cronins are recorded as hereditary owners of territory to the West of present-day Clonakilty.