Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “melatonin”

melatonin

noun [U] uk   /mel.əˈtəʊ.nɪn/ us    /-ˈtoʊ-/ specialized
a hormone in the body that produces changes in skin colour and is involved in continuing biorhythms such as our sleep patternSubstances and structures in the body
(Definition of melatonin from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
What is the pronunciation of melatonin?
Add Cambridge dictionaries to your browser to your website

Translations of “melatonin”

Word of the Day

innovate

to introduce changes and new ideas

Word of the Day

Blog

Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More