serotonin

noun

se·​ro·​to·​nin ˌsir-ə-ˈtō-nən 

ˌser-

: a phenolic amine neurotransmitter C₁₀H₁₂N₂O that is a powerful vasoconstrictor and is found especially in the brain, blood serum, and gastric mucous membrane of mammals

Examples of serotonin in a Sentence

Recent Examples on the Web

Coping with stress and anxiety during perimenopause According to Johns Hopkins Medicine, serotonin levels fall and cortisol levels rise during perimenopause. —Olivia Lee, Charlotte Observer, 10 Nov. 2025

This small chain may not be the city’s best coffee — or even the best offering on Montana Avenue — but its bright yellow cups give you the serotonin boost (in addition to the caffeine kick) that will get you through the morning. —Mia Galuppo, HollywoodReporter, 8 Nov. 2025

Sliding my feet into a fuzzy pair of slippers always gives me an instant serotonin boost. —Rylee Johnston, PEOPLE, 8 Nov. 2025

Illustration by Simone Noronha Every year, around early November, daylight-saving time kicks in—and my serotonin suddenly goes into hibernation. —Hilton Als, New Yorker, 7 Nov. 2025

Word History

Etymology

sero- + ton(ic) entry 2 or tone entry 1 + -in entry 1, probably after angiotonin, earlier name for angiotensin — more at angiotensin

Note: Term introduced by Maurice M. Rapport, Arda Alden Green and Irvine H. Page in "Crystalline serotonin," Science, vol. 108, Issue 2804 (September 24, 1948), pp. 329-330: "The general behavior of the crystalline substance is suggestive of its homogeneity. We would like provisionally to name it serotonin, which indicates that its source is serum and its activity is one of causing constriction."

First Known Use

1948, in the meaning defined above

Phrases Containing serotonin

• selective serotonin reuptake inhibitor

Rhymes for serotonin

• calcitonin
• digitonin
• melatonin
• kronen
• onan
• phonon
• ronin
• santonin

Medical Definition

serotonin

noun

se·​ro·​to·​nin ˌsir-ə-ˈtō-nən  ˌser- 

: a phenolic amine neurotransmitter C₁₀H₁₂N₂O that is a powerful vasoconstrictor and is found especially in the brain, blood serum, and gastric mucous membrane of mammals

called also 5-HT, 5-hydroxytryptamine