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Melatonin

/ˌmɛləˈtoʊnɪn/noun

A hormone released by the pineal gland in darkness, which sets the body's daily sleep rhythm.

The Greek roots

μέλας
mélās
black, dark
+
τόνος
tónos
tension, tone

Literally: dark-pigment tension

The story of the word

Aaron Lerner isolated it in 1958 while hunting a skin-whitening agent, and named it for what it did to frog melanocytes: the pigment granules pulled inward and the skin went pale. The sleep function was found afterwards. The second half of the name is borrowed from serotonin, the molecule it is made from.

How it travelled
Ancient Greek → scientific coinage → English
First recorded
1958

Same family

melancholymelaninserotoninmelanoma

In a sentence

Screen light in the evening delays the melatonin rise.

She takes half a milligram of melatonin on the first night after a long flight.

Built on the same root

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