/ Dictionary / Index C casein: Meaning and Definition of Find definitions for: ca•sein Pronunciation: (kā'sēn, -sē-in, kā-sēn'), [key] — n. a protein precipitated from milk, as by rennet, and forming the basis of cheese and certain plastics. an emulsion made from a solution of this precipitated protein, water, and ammonia carbonate. a paint in which this emulsion is used as a binder. a picture produced with this paint and emulsion. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: casein (Thesaurus) case history caseinate Related Content Daily Word Quiz: alacrity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language