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keratin Syllabification: ker·a·tin
Pronunciation: /ˈkerədən/

Definition of keratin in English:


A fibrous protein forming the main structural constituent of hair, feathers, hoofs, claws, horns, etc.
Example sentences
  • Cells are laced with a network of fibres more rigid than the rope-like structural proteins collagen and keratin.
  • Amino acids are absorbed by the body to help build keratin, the main protein in hair.
  • Cat claws are made of keratin, a protein also found in human nails.


Pronunciation: /kəˈratn-əs/
Example sentences
  • The origin of this reflection, which is the fingerprint on the diffraction pattern of the coiled coil structure in keratinous tissues, was unclear until this recent study.
  • We report a case of an unusual inflammatory reaction and multiple keratinous nodules in a thyroglossal cyst.
  • The invention also concerns methods and devices for bleaching and permanent waving of keratinous fibres using said composition.


Mid 19th century: from Greek keras, kerat- 'horn' + -in1.

  • rhinoceros from Late Middle English:

    It is the look of the rhinoceros that provides its name, which comes from Greek rhino- ‘nose’ and keras ‘horn’. The animal has been known in English since the end of the 14th century, but the first reference to it calls it a kind of unicorn. Rhino- will be familiar to gardeners from the antirrhinum (mid 16th century), the alternative name for the snapdragon, whose name means ‘counterfeiting a nose’ from its appearance, while keras appears in keratin (mid 19th century), the substance from which horn is made.

Definition of keratin in:
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