serotonin Syllabification: (ser·o·to·nin)Pronunciation: /ˌserəˈtōnən, ˌsi(ə)r-/Translate serotonin | into Italian Definition of serotonin noun Biochemistry a compound present in blood platelets and serum that constricts the blood vessels and acts as a neurotransmitter. Alternative name: 5-hydroxytryptamine; chemical formula: C10H12N2O Origin: 1940s: from serum + tonic + -in1serotonin in other Oxford dictionaries Definition of serotonin in the British & World English dictionary
