7 letters · 11 points in Scrabble
noun a fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues such as hair, feathers, nails, and hooves
originBorrowed from German Keratin, from Ancient Greek κέρας (kéras, “horn”) + -in. Doublet of carat.
Etymology from Wiktionary, CC BY-SA 3.0