melatonin
/ˌmɛləˈtoʊnɪn/ noun C2- A hormone, related to serotonin, that is secreted by the pineal gland, and stimulates colour change in the skin of reptiles, and is involved in the sleep and wake and reproductive cycles in mammals.
- Any material similar in its chemistry and effect to the natural hormone.
Plural melatonins
From the library
Sleep is partly controlled by melatonin, a hormone that makes us feel sleepy when it gets dark.
Studies have shown that during the teenage years, melatonin is released later at night, so many teenagers simply don't feel tired until eleven or even later.
Learn melatonin in real texts
With a free account, hover any word in the library for its meaning, hear it read aloud, save words for review timed to your memory, and see how much of each book you already know.