chitin

Etymology

From French chitine, from Latin chitōn (“mollusk”), from Ancient Greek χιτών (khitṓn). See also chiton.

noun

1. (biochemistry) A complex polysaccharide, a polymer of N-acetylglucosamine, found in the exoskeletons of arthropods and in the cell walls of fungi; thought to be responsible for some forms of asthma in humans.
   Chitin usually occurs throughout Invertebrates in the form of an investment to the outermost cellular layer or ectoderm. 1880, Arthur Gamgee, A Text-book of the Physiological Chemistry of the Animal Body, Macmillan, page 299
   The robot’s energy source is the sugar in the polysaccharide called chitin that makes up a fly’s exoskeleton. 11 Sep 2004, New Scientist, page 19