Etymologically
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chlorine

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Pronunciation

  • /ˈklɔɹin/, /ˈklɔːɹiːn/[1]

Etymology

It was coined in 1810 by the English chemist Sir Humphry Davy,[2][3][4][5] formed from English chloro- + -ine from Ancient Greek χλωρός (khlōrós, “pale green, greenish yellow”),[2][4][6][7] with allusion to the colour of the gas.[2][3][4] Etymonline derives the Greek adjective from Proto-Indo-European *ghel- (“to shine”), whose derivatives denote green and yellow.[3] The OED compares German Chlorine (1811 or earlier), and the later French chlore and Chlor (both 1814).[2] Klein compares bromine, fluorine and iodine.[6]

Earliest recorded meaning

The chemical element, a yellowish-green pungent gas: 1810, in Davy's paper read to the Royal Society on 15 November.[2][4]

Semantic evolution

The gas had been discovered by the Swedish chemist Carl Scheele in 1774 and was called oxymuriatic acid gas;[4][3] Davy first identified it as an element and named it after its colour.[4][5] Etymonline adds the older name dephlogisticated marine acid.[3] From 1832 the word was also used of a chlorine compound, such as a bleach or disinfectant, and since 1864 of an atom or ion of chlorine.[2] Ayto notes that chloroform, originally French, is a secondary formation based on the name of the element, while chlorophyll was named directly for its green colour.[5]

Timeline

  • 1774 – the gas is discovered by Scheele, as oxymuriatic acid gas.[4][3]
  • 1810 – named chlorine by Davy.[2][3][4]
  • 1832 – a chlorine compound; a bleach or disinfectant.[2]
  • 1864 – an atom or ion of chlorine.[2]

Meanings

Noun

  1. A toxic, pungent, greenish-yellow gas, a chemical element of the halogen group (atomic number 17, symbol Cl), used in water treatment, as a bleach and disinfectant, and in making many chemicals.[8][9][2]
  2. A chlorine compound used as a bleach or disinfectant: The pool smelled strongly of chlorine.[2]

Word family

  • chlorinous
  • antichlor
  • chloro-
  • chloral
  • chloric
  • chloride
  • chlorinate
  • chlorate
  • chlorophyll
  • chloroform
  • bromine
  • fluorine
  • iodine

Usage notes

A rare adjective chlorine, light green or grass-green, is recorded from before 1849, in Poe.[2][9][10]

References

  1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  3. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  4. ^ a b c d e f g h Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  5. ^ a b c Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
  6. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
  7. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
  8. ^ Collins English Dictionary (2023), Glasgow: HarperCollins
  9. ^ a b Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  10. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press