keratin
Concise Oxford English Dictionary © 2008 Oxford University Press:
keratin /ˈkɛrətɪn/
▶noun any of a group of fibrous proteins forming the main structural constituent of hair, nails, feathers, hoofs, claws, and horns.
– derivatives
keratinous adjective.
keratinous adjective.
'keratin' also found in these Oxford entries:

