ren·​nin | \ ˈre-nən How to pronounce rennin (audio) \

Definition of rennin

: an enzyme that coagulates milk and is used in making cheese and junkets especially : one from the mucous membrane of the stomach of a calf

First Known Use of rennin

1889, in the meaning defined above

History and Etymology for rennin

rennet + -in entry 1

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The first known use of rennin was in 1889

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Cite this Entry

“Rennin.” Dictionary, Merriam-Webster, Accessed 21 Feb. 2020.

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ren·​nin | \ ˈren-ən How to pronounce rennin (audio) \

Medical Definition of rennin

: a crystallizable enzyme that coagulates milk, that occurs especially with pepsin in the gastric juice of young animals and is obtained as a yellowish powder, grains, or scales usually by extraction of the mucous membrane of the fourth stomach of calves, and that is used chiefly in making cheese and casein for plastics

called also chymosin

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