Transferred use of the Scottish surname, in origin a local name from any of various places named with Gaelic blàr ‘plain, field’. Outside Scotland, where it is a male name, it is found chiefly in North America, where it is also popular for girls.
Irish: 1. reduced Anglicized form of Gaelic Ó Taidhg ‘descendant of Tadhg’, a byname meaning ‘bard’, ‘poet’, ‘philosopher’. 2. In Ulster it is sometimes an Anglicization of Mac Taidhg, which is more commonly Anglicized as McCaig.