[Ir., world (?)].
In the pseudo-history Lebor Gabála [Book of Invasions], an apocryphal son of Noah who was denied entry to the Ark. With the counsel of his daughter, Cesair, he built an idol who commanded him to build a ship and take refuge in it. Bith, Cesair, and others sailed for seven years before they reached Ireland, in a company of fifty women and only three men. Bith took one of Cesair's companions as well as sixteen other women and settled in the north, where he died before the Flood. Another son was Adná. Reputed eponym of Sliab Betha [Slieve Beagh] in Northern Ireland.