Meaning of pyrrole

pyr•role

Pronunciation: (pi-rōl', pir'ōl), [key]
— n. Chem.
  1. 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.