Definition of serotonin noun from the Oxford Advanced American Dictionary

 

serotonin

 noun
noun
NAmE//ˌsɛrəˈtoʊnən//
 
[uncountable]
 
jump to other results
a chemical in the brain that affects how messages are sent from the brain to the body, and also affects how a person feels the feel-good hormone serotonin serotonin—the happiness hormone
See the Oxford Advanced Learner's Dictionary entry: serotonin