First Known Use: 1958
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
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Origin of MELATONIN
Greek melas black + -tonin (as in serotonin)
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
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