Main Entry: por·phy·rin

Pronunciation: \ˈpȯr-fə-rən\

Function: noun

Etymology: International Scientific Vocabulary, from Greek porphyra purple

Date: 1910

: any of various compounds with a macrocyclic structure that consists essentially of four pyrrole rings joined by four =CH− groups; especially : one (as chlorophyll or hemoglobin) containing a central metal atom and usually exhibiting biological activity