Definitions for keratinˈkɛr ə tɪn
Random House Webster's College Dictionary
ker•a•tinˈkɛr ə tɪn(n.)
a tough, insoluble protein that is the main constituent of hair, nails, horn, hoofs, etc., and of the outermost layer of skin.
Origin of keratin:
1840–50; < Gk kerat-, s. of kérashorn+ -in1
ke•rat•i•nouskəˈræt n əs(adj.)
a fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues such as hair, feathers, nails, and hooves
A protein which hair and nails are comprised of.
a nitrogenous substance, or mixture of substances, containing sulphur in a loose state of combination, and forming the chemical basis of epidermal tissues, such as horn, hair, feathers, and the like. It is an insoluble substance, and, unlike elastin, is not dissolved even by gastric or pancreatic juice. By decomposition with sulphuric acid it yields leucin and tyrosin, as does albumin. Called also epidermose
The Nuttall Encyclopedia
a substance forming the chief constituent in the hair, nails, and horn of animals.