melatonin

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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

Recent Examples of melatonin from the Web

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Origin and Etymology of melatonin

Greek melas black + -tonin (as in serotonin)


Medical Dictionary

melatonin

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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

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