Dunn is a surname of English, Irish, and Scottish origin, derived from the Old English word dunn meaning "dark" or the Gaelic donn meaning "brown," originally used to describe a person's hair color or complexion. The Irish variant often stems from the Anglicized form of the Gaelic Ó Duinn ("descendant of Donn"), where Donn itself was a byname for someone with brown hair. The surname is widespread in Ireland and Scotland, with notable bearers including the Irish poet John Dunn (18th century) and the American musician Ronnie Dunn of the country duo Brooks & Dunn.