- A fibrous protein forming the main structural constituent of hair, feathers, hoofs, claws, horns, etc..More 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.
mid 19th century: from Greek keras, kerat- 'horn' + -in1.
More definitions of keratinDefinition of keratin in:
- The US English dictionary