/ Dictionary / Index P prostacyclin: Meaning and Definition of Find definitions for: pros•ta•cy•clin Pronunciation: (pros"tu-sī'klin), [key] — n. Biochem. a prostaglandin, CHO, that specifically inhibits the formation of blood clots. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. prost prostaglandin Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language