/ Dictionary / Index P pyrrole: Meaning and Definition of Find definitions for: pyr•role Pronunciation: (pi-rōl', pir'ōl), [key] — n. Chem. a colorless, toxic, liquid, five-membered ring compound, CHN, that is a component of chlorophyll, hemin, and many other important naturally occurring substances. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Pyrrhus pyrrolidine Related Content Daily Word Quiz: portent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language