Definition of "serotonin"
serotonin
/ˌsɛɹəˈtəʊnɪn/
noun
countable and uncountable, plural serotonins
(biochemistry) An indoleamine neurotransmitter, 5-hydroxytryptamine, that is involved in depression, appetite, etc., and is crucial in maintaining a sense of well-being, security, etc.