Mainly North American: transferred use of the surname, originally a Norman baronial name (d'Airelle) borne by a family who came from Airelle in Calvados. It was first used as a given name towards the end of the 19th century.
Irish (especially Ulster): 1. Anglicized form of a rare Gaelic name, Mac Nuadhat, a patronymic from the personal name Nuadha, the name of an ancient Celtic god. 2. (originally Scottish) reduced form of McNaughton.