ca·​sein | \ ˈkā-ˌsēn How to pronounce casein (audio) , kā-ˈsēn \

Definition of casein

: a phosphoprotein of milk: such as
a : one that is precipitated from milk by heating with an acid or by the action of lactic acid in souring and is used in making paints and adhesives
b : one that is produced when milk is curdled by rennet, is the chief constituent of cheese, and is used in making plastics

Examples of casein in a Sentence

Recent Examples on the Web Both whey and casein protein have shown similar benefits. Sarah Schlichter, Outside Online, 11 Feb. 2021 The technology, which has been around since the 1930s, generally involves blending casein with something like acrylonitrile (the chemical used to make acrylic), making milk cotton a semi-synthetic fabric. New York Times, 22 Apr. 2021 Three weeks in, she was diagnosed with cow’s milk protein intolerance, an allergy that causes extreme gastrointestinal pain and required me to eliminate anything with lactose, whey, casein or soy from my diet. Katie Gutierrez, Time, 5 Nov. 2021 Occasionally, bottles are fined, or clarified, with animal products like egg whites, milk casein or isinglass, which comes from fish. New York Times, 15 Jan. 2021 These solids can be washed and dried to create casein protein powders. Carsen Joenk, Popular Science, 11 Jan. 2021 Common fining agents including gelatin, which is an animal product, and casein, which is a protein from milk. Tirion Morris, The Arizona Republic, 8 Dec. 2020 Once its pH hits 4.6, that’s when casein (milk protein) clumps. J. Kenji López-alt, New York Times, 14 Apr. 2020 Dairy products from mammals contain a protein called casein that attracts those hot capsaicin molecules so that dairy molecules can dissolve them, according to the American Chemical Society. Sophie Saint Thomas, SELF, 12 Oct. 2018 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'casein.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of casein

1823, in the meaning defined above

History and Etymology for casein

probably from French caséine, from Latin caseus cheese

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Cite this Entry

“Casein.” Dictionary, Merriam-Webster, Accessed 27 May. 2022.

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More Definitions for casein


ca·​sein | \ kā-ˈsēn How to pronounce casein (audio) \

Kids Definition of casein

: a whitish to yellowish protein that is found in milk and cheese and is used in making paints, plastics, and adhesives


ca·​sein | \ ˈkā-ˌsēn, ka-ˈsēn How to pronounce casein (audio) \

Medical Definition of casein

: any of several phosphoproteins of milk: as
a : one that occurs as a colloidal suspension in milk

called also caseinogen

b : one that is produced when milk is curdled by rennet, is the chief constituent of cheese, and is used in making plastics

called also paracasein

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