Ó Ciardubháin
Ó CIARDUBHÁIN—I—O Kerevan, O Kerrywane, O'Kirwan, Kierevan, Kiervan, Kirivan, Kerevan, Kerivan, Kirvan, Kirwan, Kirwin, &c.; 'descendant of Ciardubhán' (diminutive of ciardubh, jet-black); the name of a family who were anciently erenaghs of Louth, and apparently of another family in Co. Clare. The Kirwans were in later times an important family in the city of Galway. Their claim to be of English origin is rightly denied by O'Donovan, there being no such English family name.
Alphabetical Index to Irish Surnames