chitin (n.)

"organic substance forming the wing cases of beetles and other insects," 1836, from French chitine, from Latinized form of Greek khiton "frock, tunic, garment without sleeves worn directly on the body;" in reference to soldiers, "coat of mail," used metaphorically for "any coat or covering." "Probably an Oriental word" [Liddell & Scott]; Klein compares Hebrew (Semitic) kuttoneth "coat," Aramaic kittana, Arabic kattan "linen;" Beekes compares Phoenician ktn "linen garment." Related: Chitinous.