a Celtic language that includes the speech of ancient Ireland and the dialects that have developed from it, especially those usually known as Irish, Manx, and Scottish Gaelic: Gaelic constitutes the Goidelic subbranch of Celtic.
a branch of the Indo-European family of languages, including especially Irish, Scottish Gaelic, Welsh, and Breton, which survive now in Ireland, the Scottish Highlands, Wales, and Brittany. Celt, Celt.
