/ Dictionary / Index T tissue plasminogen activator: Meaning and Definition of Find definitions for: tis'sue plasmin'ogen ac'tivator Pronunciation: [key] — Biochem. Biochem. an anticlotting enzyme, naturally occurring in small amounts in the blood. the same enzyme, produced in large amounts by genetic engineering techniques for use in dissolving blood clots. Abbr.: TPA Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. tissue paper tissue typing Related Content Daily Word Quiz: placid Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language