/ Dictionary / Index P protamine: Meaning and Definition of Find definitions for: prot•a•mine Pronunciation: (prō'tu-mēn", pro-tam'in), [key] — n. Biochem. any of a group of arginine-rich, strongly basic proteins that are not coagulated by heat, occurring primarily in the sperm of fish. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: protamine (Thesaurus) Protagoras protanomaly Related Content Daily Word Quiz: miscreant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language