[ kahy-tin ]
/ ˈkaɪ tɪn /

noun Biochemistry.

a nitrogen-containing polysaccharide, related chemically to cellulose, that forms a semitransparent horny substance and is a principal constituent of the exoskeleton, or outer covering, of insects, crustaceans, and arachnids.

Nearby words

  1. chit,
  2. chita,
  3. chital,
  4. chitarrone,
  5. chitchat,
  6. chitlin circuit,
  7. chitlings,
  8. chiton,
  9. chitosan,
  10. chittagong

Origin of chitin

1830–40; < French chitine < Greek chit(ṓn) tunic, chiton + French -ine -in2

Related formschi·tin·ous, chi·tin·oid, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for chitinous

British Dictionary definitions for chitinous


/ (ˈkaɪtɪn) /


a polysaccharide that is the principal component of the exoskeletons of arthropods and of the bodies of fungi
Derived Formschitinous, adjectivechitinoid, adjective

Word Origin for chitin

C19: from French chitine, from Greek khitōn chiton + -in

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for chitinous



1836, from French chitine, from Greek khiton "frock, tunic," of soldiers, "coat of mail," used metaphorically for "any coat or covering." "Probably an Oriental word" [Liddell & Scott]. Klein compares Hebrew kuttoneth, Aramaic kittana, Arabic kattan "linen."

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for chitinous


[ kītn ]


A tough, protective, semitransparent polysaccharide forming the principal component of arthropod exoskeletons and the cell walls of certain fungi.
Related formschitin•ous adj.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for chitinous


[ kītn ]

A tough, semitransparent substance that is the main component of the exoskeletons of arthropods, such as the shells of crustaceans and the outer coverings of insects. Chitin is also found in the cell walls of certain fungi and algae. Chemically, it is a nitrogenous polysaccharide (a carbohydrate).
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.