/ Dictionary / Index P plasminogen: Meaning and Definition of Find definitions for: plas•min•o•gen Pronunciation: (plaz-min'u-jun, -jen"), [key] — n. Biochem. the blood substance that when activated forms plasmin. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: plasminogen (Thesaurus) plasmin plasmo- Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language