Etymologically
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quadrant

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Pronunciation

  • /ˈkwɒd.ɹənt/, /ˈkwɑ.dɹənt/[1]

Etymology

It is borrowed from Anglo-Norman quadrant, also quadran and cadran,[2] and directly borrowed from Latin quadrāns (“a fourth part, quarter”), stem quadrant-.[2][3][4][5][6][7] Etymonline traces it through Old French quadrant, also cadran, the name of a Roman coin and of a sundial.[8] In French the word is recorded for the angle-measuring instrument from the 13th century, for a quarter from before 1324 and for a quarter of a day from 1482;[2] the Anglo-Norman word, recorded from 1396–1404, meant the instrument and a clock face.[9] The Latin noun is the present participle of quadrō (“to make square; to fit”), used as a noun,[2][8][5] and stood for a quarter of the coin called as, or of an acre, a foot, a pound or a day; in post-classical use in British sources it also meant a farthing, the angle-measuring instrument (13th century) and a quarter of a circle.[2][8] It is related to quadrus (“a square”) and quattuor (“four”),[8][3][6] from Proto-Indo-European *kwetwer- (“four”).[8][7]

Earliest recorded meaning

A quarter of a day, six hours: before 1398, in John Trevisa's translation of Bartholomaeus Anglicus's De Proprietatibus Rerum.[2][3] Etymonline dates this sense to the late 14th century.[8]

Semantic evolution

The instrument for measuring angles and altitudes, made as a graduated quarter-circle, is recorded from about 1400, and is named for that shape.[2][3][8][10] The word was also used for a farthing (about 1450, in a Scottish source) and for the Roman coin worth a quarter of an as (1533).[2] The geometrical sense, a quarter of a circle, is recorded from 1559 in the OED,[2] while Barnhart dates it to 1571 and Etymonline to the 1570s.[3][8] Johnson (1755) gave three senses: the fourth part, the quarter of a circle, and the instrument.[11] From the late 16th century it was used of anything shaped like a quarter-circle (1581) and of any of four parts of a thing (1587); a street curved in a quarter-circle was a quadrant from 1819, especially the end of Regent Street in London by Piccadilly Circus.[2] The astronomical quadrants of the moon (1859) and the quarters of an area of the body in anatomy and medicine (1864) follow German Quadrant.[2] In the mining districts of Northumberland and Durham a quadrant was an L-shaped beam that turned a horizontal motion into a vertical one, as in pumping.[12]

Timeline

  • before 1398 – a quarter of a day; six hours.[2][3]
  • c. 1400 – an instrument for measuring angles and altitudes.[2][3][8]
  • c. 1450 – a farthing.[2]
  • 1533 – a Roman coin worth a quarter of an as.[2]
  • 1559 – a quarter of a circle.[2] Barnhart dates this sense to 1571.[3]
  • 1587 – any of four parts into which something is divided.[2]
  • 1819 – a street curved in a quarter-circle.[2]
  • 1864 – in anatomy and medicine, any of four quarters of an area of the body.[2]

Meanings

Noun

  1. (geometry) A quarter of the circumference of a circle; an arc of 90 degrees.[13][7]
  2. (geometry) The area bounded by such an arc and two perpendicular radii.[13][7][2]
  3. (geometry) Any of the four regions into which a plane is divided by the axes of a Cartesian coordinate system.[13][7]
  4. Any of four parts into which something is divided, as an area of the body in medicine: pain in the lower right quadrant of the abdomen.[2]
  5. A part of a machine shaped like a quarter-circle, as a cam or a gear sector.[13][6]
  6. An instrument with a graduated arc of 90 degrees and a sight, formerly used in astronomy, navigation and surveying to measure altitudes.[13][6][2]
  7. (obsolete) A quarter of a day; six hours.[2][14]

Word family

  • quadrantal
  • quadrantlike

Usage notes

The OED and the Shorter Oxford record a rare noun quadrant meaning a square or a quadrangle, from 1443, apparently an alteration of quadrat or quadrate influenced by this word,[2][14][6] and an adjective meaning square, or in agreement with something, from 1517, now obsolete.[2][14]

References

  1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l m n o p q r s t u v w x y Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  3. ^ a b c d e f g h Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  4. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
  5. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
  6. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  7. ^ a b c d e The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
  8. ^ a b c d e f g h i Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  9. ^ Anglo-Norman Dictionary (AND2), Aberystwyth University, anglo-norman.net (2nd ed., 2005–)
  10. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
  11. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
  12. ^ Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)
  13. ^ a b c d e Collins English Dictionary (2023), Glasgow: HarperCollins
  14. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press