melatonin Hear it!

melatonin definition

mela·to·nin (mel′ə tō′nin)

noun

a hormone, CHNO, produced by the pineal body, that lightens skin pigmentation, inhibits estrus, etc.: its secretion is inhibited by sunlight

Etymology: mela(no)- + ton(ic) + -in

Webster's New World College Dictionary Copyright © 2009 by Wiley Publishing, Inc., Cleveland, Ohio.
Used by arrangement with John Wiley & Sons, Inc.

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