Chitin

n.

1.

(Chem.) A white amorphous horny substance forming the harder part of the outer integument of insects, crustacea, and various other invertebrates; entomolin.

Noun

1.

chitin - a tough semitransparent horny substance; the principal component of the exoskeletons of arthropods and the cell walls of certain fungi

polyose, polysaccharide