Definitions
hormone secreted by the pineal gland
Word origin
From mela- + tone + -in, ultimately from Ancient Greek μέλας (mélas, “black, dark”).
Used in a sentence
“How exactly melatonin relates to sleep is still not understood.”
“Melatonin production can be delayed or arrested by even brief flashes of bright light entering the eye, research has shown.”
Source: Wiktionary, CC BY-SA 4.0
Used as a crossword answer1 curated clues
01“Sleep-cycle hormone”9 letters
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