keratin Meaning, Definition & Usage

  1. noun a fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues such as hair, feathers, nails, and hooves
    ceratin.

WordNet

Ker"a*tin noun
Etymology
Gr. , , horn.
Definitions
  1. (Physiol. Chem.) 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. a sulfur-containing fibrous proein.

Webster 1913