Dictionary
en•dor•phin
Pronunciation: (en-dôr'fin), [key]—
n.
any of a group of peptides occurring in the brain and other tissues of vertebrates, and resembling opiates, that react with the brain's opiate receptors to raise the pain threshold.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.