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equation

Etymology and origin of the English word equation

History Permalink
Confidence
Established
Formation
Borrowing
First attested
c. 1386
From
Middle English equacioun
Ultimate origin
Latin (aequatio)

Pronunciation

  • IPA: /ɪˈkweɪ.ʒən/, /-ʃən/ (UK); /ɪˈkweɪ.ʒən/ (US)[1]

Etymology

It is inherited from Middle English equacioun, from French équation[2][3] or directly from Latin aequātiō (“an equal distribution, a sharing in common”), aequātiōnem,[2][4] from aequāre, to make equal (see equate, equal).[2][5]

Earliest recorded meaning

In astrology, equal division, as the equation of houses: about 1386, the late 14th century in Etymonline.[6][2]

Semantic evolution

In medicine, making proportionate, it is from the early 15th century.[2] The mathematical sense, a statement that two expressions are equal, joined by an equals sign, is from the 1560s (1570).[2][6] In astronomy, a correction added to or subtracted from an observed result is from 1666.[6] The general action of making equal or balancing is by the 1650s (1656).[2][6] Equation of payments is from 1677.[6] The chemical equation is by 1807.[2] A situation with many factors, as in that doesn't come into the equation, is a modern figurative use.[7]

Timeline

  • c. 1386 – equal partition (astrology).[6]
  • early 15th century – making proportionate.[2]
  • 1570 – a mathematical equation.[6]
  • 1656 – making equal.[6]
  • 1807 – a chemical equation.[2]

Modern meaning

Noun

  1. (mathematics) A statement that two expressions are equal, joined by an equals sign.
  2. (chemistry) A representation of a chemical reaction with reactants and products.
  3. The act of regarding as equal; equating.
  4. A situation with several interacting factors.

Word family

  • equational
  • equationally

References

  1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  3. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
  4. ^ Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  5. ^ Pearsall, Judy, ed. (1998), The New Oxford Dictionary of English, Oxford: Clarendon Press
  6. ^ a b c d e f g h Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
  7. ^ Collins English Dictionary (2023), Glasgow: HarperCollins
Cite this entry

“Equation.” Etymologically, 17 Oct. 2026, etymologically.com/en/equation. Accessed 17 Oct. 2026.

Last edited on . ·