The Scottish and Irish surname Dunn is of patronymic origin. He name Dunn is the anglicized form of Gaelic name Ó Duinn, Ó Doinn meaning  “descendant of Donn”, a byname meaning “brown-haired”or “chieftain”. In Ireland, those who spelt their name Dunn usually came from Ulster, where they were possibly of Scottish extraction. The first recorded spelling of the family name is shown to be that of Gillananaomh O'Duinn, which was dated 1102, in the "Ancient Irish Records", during the reign of Irish High Kings in Opposition, 1103 - 1169.The earliest Scottish reference was Adam de Dun in 1255. Buy family crest jewelry for a man or a woman.