Etymologically
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serotonin

This is the current revision of this entry, as edited by bogdan on 1 November 2026 at 01:08. This address is a permanent link to this version.
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Pronunciation

  • UK: /ˌsɛɹəˈtəʊnɪn/[1]
  • US: /ˌsɛɹəˈtoʊnɪn/[1]

Etymology

It was coined from English sero- + tonic + -in:[2][3][4][5][6] sero- is the combining form of serum,[2] the middle element is taken from the adjective tonic,[3][7] and -in is the suffix of chemical names.[2] Merriam-Webster explains the name by the substance's constricting effect on blood vessels.[7] The American Heritage Dictionary and Dictionary.com take the middle part from tone instead.[8][9]

Earliest recorded meaning

The compound 5-hydroxytryptamine, found in blood serum: 1948, in a paper by M. M. Rapport and others in Science.[3][2][7]

Semantic evolution

The name was given for the substance's presence in blood serum and its action in constricting blood vessels.[7][10] It is now best known as a neurotransmitter, also found in the brain, the intestines and the blood platelets,[6][10] and the OED's definition includes its role in vasoconstriction, anaphylactic shock and the regulation of daily cycles.[3][4] The adjective serotonergic is formed from it.[4]

Timeline

  • 1948 – the compound 5-hydroxytryptamine.[3][2][7]

Meanings

Noun

  1. A compound, 5-hydroxytryptamine, present in the brain, intestines and blood platelets, which acts as a neurotransmitter and causes vasoconstriction: Some antidepressants raise serotonin levels in the brain.[6][10][7]

Word family

  • selective serotonin reuptake inhibitor

References

  1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  3. ^ a b c d e Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  4. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
  5. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
  6. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins
  7. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  8. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
  9. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
  10. ^ a b c Soanes, Catherine; Stevenson, Angus, eds. (2004), Concise Oxford English Dictionary, 11th ed., Oxford: Oxford University Press