noun, noun which may take the genitive case particle 'no'
keratin; horny substance; corneum; cuticle; collagen
Refers to the tough protein material in skin, hair, nails, and horns. In cosmetic contexts, often relates to dead skin cells or calluses. The gloss 'collagen' is less common; primarily means keratin.
I use a cream that softens keratin.
The callus on my heel has gotten thick.
keratinization; cornification
stratum corneum; horny layer; cornified layer
skin thickening; hyperkeratosis
exfoliation; skin cleansing
Compound of 角 (horn, angle) and 質 (substance, quality). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning 'horny substance'.