The barbiton, or barbitos (Gr: βάρβιτον or βάρβιτος; Lat. barbitus), is an ancient stringed instrument related to the lyre known from Greek and Roman classics.
The Greek instrument was a bass version of the kithara, and belonged in the zither family, but in medieval times, the same name was used to refer to the barbat; a different instrument that is a variety of lute.