Etymologically
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triangle

This is the current revision of this entry, as edited by bogdan on 17 October 2026 at 15:35. This address is a permanent link to this version.
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Pronunciation

  • IPA: /ˈtraɪ.æŋ.ɡəl/[1]

Etymology

It is inherited from Middle English triangle, borrowed from Old French triangle and directly Latin triangulum (“triangle”), the noun use of the neuter of triangulus (“three-cornered”),[2][3][4][5][6] from tri- (“three”) and angulus (“corner, angle”) (see angle).[2][3][5]

Earliest recorded meaning

A figure with three sides and three angles: 1392 in Barnhart, 1398 in the OED.[2][7]

Semantic evolution

A three-cornered carpenter's instrument is from about 1400,[3] and the constellation Triangulum from the mid-15th century.[3][7] A triangle used as a symbol, as of the Trinity, is from 1584,[7] and figuratively a group of three from 1621, especially a love affair of three people.[7] The musical instrument, a steel rod bent into a triangle, is by 1801.[3] The Bermuda Triangle is from 1964.[7] Triangular is from before 1400, in a translation of Lanfranc,[2] and triangulate from 1833, in Herschel.[2] In Northamptonshire dialect triangle-ways meant cross-cornered.[8]

Timeline

  • 1392 – a triangle.[2]
  • c. 1400 – a carpenter's triangle.[3]
  • 1584 – a symbolic triangle.[7]
  • 1621 – a group of three.[7]
  • 1801 – the musical triangle.[3]
  • 1964 – the Bermuda Triangle.[7]

Modern meaning

Noun

  1. A plane figure with three sides and three angles.
  2. Anything shaped like a triangle.
  3. A situation involving three parties, especially a love affair: the eternal triangle.
  4. (music) A percussion instrument made of a steel rod bent into a triangle, struck with a metal beater.
  5. A flat three-sided guide used in drawing.

Word family

  • triangled
  • angle
  • triangular
  • triangulate
  • tri-

References

  1. ^ Jones, Daniel (2011), Cambridge English Pronouncing Dictionary, 18th ed., ed. Peter Roach, Jane Setter and John Esling, Cambridge: Cambridge University Press
  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. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
  5. ^ a b Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  6. ^ Pearsall, Judy, ed. (1998), The New Oxford Dictionary of English, Oxford: Clarendon Press
  7. ^ 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
  8. ^ 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)