Donnchadh (Scottish Gaelic pronunciation: [ˈt̪ɔn̪ˠɔ.xəɣ])[1] is a masculine given name common to the Irish and Scottish Gaelic languages. It is composed of the elements donn, meaning "brown" or "dark" from Donn a Gaelic God; and chadh, meaning "chief" or "noble".[2][3][4] The name is also written as Donnchad, Donncha, Donnacha, Donnchadha and Dúnchad. Modern versions include (in Ireland) Donnacha, Donagh, Donough, Donogh and (in Scotland) Duncan.
The Irish surnames Donough, McDonagh, McDonough, O'Donoghue and Dunphy among others are derived from the given name (In Gaelic: Mac – son of, Ó – of the family of). Another derivation is the name of the Scottish Clan Donnachaidh.[citation needed]