Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “keratin”


noun [U]     /ˈker.ə.tɪn/ specialized
a strong natural protein, the main substance that forms hair, nails, hoofs, horns, feathers, etc.Substances and structures in the body
(Definition of keratin noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
Focus on the pronunciation of keratin

Word of the Day


an ability to do things in the stated, especially positive, way

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More