keratin

noun

ker·​a·​tin ˈker-ə-tən How to pronounce keratin (audio)
: any of various sulfur-containing, fibrous, acidic or basic proteins chiefly of epithelial cells and tissues that are relatively insoluble and resistant to degradation, form filaments which assemble into bundles to provide structural support, and are the primary component of hair, nails, horns, claws, hooves, quills, scales, feathers and the epidermal layer of skin

Note: In addition to its structural properties, keratin also plays a role in cell growth and proliferation, cellular transport of substances, and intercellular communication.

Rhino horn is not actually horn but densely compacted fibers of keratin, a protein found in hair and fingernails.Maryanne Vollers
Wool fibers are composed of keratin proteins bundled into microfibrils.A. Goho
compare keratinocyte
keratinous adjective

Examples of keratin in a Sentence

Recent Examples on the Web At each of your fingertips there’s an ever-growing, translucent plate of fibrous protein called keratin, otherwise known as a nail. Sabrina Sholts, Smithsonian Magazine, 12 Mar. 2024 The volumizing formula is enhanced with hydrating hyaluronic acid, vitamin E, and keratin to boost shine and lash thickness while replenishing brittle lashes. Sophie Dodd, Peoplemag, 7 Jan. 2024 Hair dye, scissors, and keratin treatments do not evaporate once someone enters into their second Saturn Return. Daniel Rodgers, Vogue, 23 Feb. 2024 Baleen–or whalebone–is a hard substance made up of keratin. Laura Baisas, Popular Science, 21 Feb. 2024 And in nail strengtheners, formaldehyde is supposed to bond with the nail’s keratin. Marci Robin, Allure, 29 Jan. 2024 These supplements are meant to support collagen, elastin, and keratin production, the latter of which is the primary protein in hair. Neha Tandon, Glamour, 13 Sep. 2023 This formula is enriched with keratin, biotin, and zinc, which work together to support hair growth while strengthening strands and reducing shedding. Jessie Quinn, Peoplemag, 13 Feb. 2024 Just like with a stye (and most eyelid bumps), a pimple is caused by an oil gland getting blocked by a mix of skin cells, oil, and keratin, creating inflammation within the follicle. Chloe Metzger, Allure, 15 Dec. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'keratin.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

borrowed from German Keratin, from Greek kerat-, stem of kéras "horn" + German -in -in entry 1 — more at kerato-

Note: The term was introduced by the German physician and chemist Johann Franz Simon (1807-43) in Handbuch der angewandten medizinischen Chemie, 1. Theil, Medizinisch-analytische Chemie (Berlin, 1840), p. 49.

First Known Use

circa 1849, in the meaning defined above

Time Traveler
The first known use of keratin was circa 1849

Dictionary Entries Near keratin

Cite this Entry

“Keratin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/keratin. Accessed 29 Mar. 2024.

Kids Definition

keratin

noun
ker·​a·​tin ˈker-ət-ᵊn How to pronounce keratin (audio)
: a sulfur-containing protein that makes up hair and horny tissues (as nails)

Medical Definition

keratin

noun
ker·​a·​tin ˈker-ət-ən How to pronounce keratin (audio)
: any of various sulfur-containing fibrous proteins that form the chemical basis of horny epidermal tissues (as hair and nails) and are typically not digested by enzymes of the gastrointestinal tract see pseudokeratin

More from Merriam-Webster on keratin

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