Etymologically
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thermometer

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Pronunciation

  • UK: /θəˈmɒm.ɪ.tə/[1]
  • US: /θɚˈmɑ.mɪ.tɚ/[1]

Etymology

It is borrowed from French thermomètre,[2][3][4][5][6] a word first recorded in 1624 and coined by the Jesuit Jean Leuréchon,[3][5] from Ancient Greek θέρμη (thérmē, “heat”)[5][4][7][6] or θερμός (thermós, “hot”)[3][2] and μέτρον (métron, “measure”),[3][2][5] from Proto-Indo-European *me- (“to measure”).[3] The OED treats it as a modern formation from the same Greek words,[8] and the Oxford Dictionary of English also allows New Latin thermometrum as the source.[9] According to Ayto, the Greek noun goes back to Proto-Indo-European *ghwerm-, which probably also gave warm.[6] The Latinate name thermoscopium is recorded a little earlier, in the 1610s.[3][2][8]

Earliest recorded meaning

An instrument for measuring temperature: 1633, in an English translation of Mathematical Recreations.[8][2][4] Etymonline notes that the earliest such device was Galileo's air thermometer of about 1597, and that the familiar mercury-in-glass thermometer was invented by Fahrenheit in 1714.[3]

Semantic evolution

Johnson (1755) defined it as an instrument for measuring the heat of the air or of any matter.[10] The figurative use, for something that shows the state or level of a feeling or opinion, appears in 1801, in Alexander Hamilton.[8]

Timeline

  • 1633 – an instrument for measuring temperature.[8][2][4]
  • 1801 – figurative use.[8]

Meanings

Noun

  1. An instrument for measuring temperature, typically a sealed glass tube with a column of mercury or alcohol that rises and falls along a graded scale.[11][4][8]
  2. (figurative) Something that shows the level or state of a feeling, opinion or condition.[8]

Word family

  • thermometric
  • thermometrically

References

  1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  3. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  4. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  5. ^ a b c d Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
  6. ^ a b c Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
  7. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
  8. ^ a b c d e f g h Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  9. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
  10. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
  11. ^ Collins English Dictionary (2023), Glasgow: HarperCollins