The surname Dunn has several different origins. In some cases it is an Anglicised form of the Irish surname Ó Duinn, meaning "grandson of Donn"; the Gaelic Donn was originally a byname, meaning "brown-haired" or "chieftain". Another origin of the surname Dunn is from the Middle English dunn, meaning "dark-coloured"; this name originated as a nickname for one with dark hair or skin. Another origin is from a habitative name, derived from Dun in Angus, Scotland; this place name is derived from the Scottish Gaelic dùn, meaning "fort". Another origin is from the Gaelic donn, meaning "brown"