chiton /ˈkaɪtn̩/ noun2 •(historical) A loose woolen tunic worn by men and women in Ancient Greece and in Ancient Rome.On the night of our first attempt, we simply overdrank and passed out in our chitons in the woods near Francis’s house. — 1992 •Any of various rock-clinging marine molluscs of the class Polyplacophora, including the genus Chiton.In the giant chiton, Cryptochiton, this girdle has expanded so as to completely cover the plates. — 1969 formschitones · chitons