Dictionary

melatonin

noun mel·a·to·nin \ˌme-lə-ˈtō-nən\

Definition of MELATONIN

:  a vertebrate hormone that is derived from serotonin, is secreted by the pineal gland especially in response to darkness, and has been linked to the regulation of circadian rhythms
ADVERTISEMENT

Origin of MELATONIN

Greek melas black + -tonin (as in serotonin)
First Known Use: 1958
Medical Dictionary

melatonin

noun mel·a·to·nin \ˌmel-ə-ˈtō-nən\

Medical Definition of MELATONIN

:  a vertebrate hormone C13H16N2O2 that is derived from serotonin, is secreted by the pineal gland especially in response to darkness, and has been linked to the regulation of circadian rhythms

Browse

Next Word in the Dictionary: melba toastPrevious Word in the Dictionary: melanoticAll Words Near: melatonin
How to use a word that (literally) drives some people nuts.
Test your vocab with our fun, fast game
Ailurophobia, and 9 other unusual fears