triangle

From Middle English triangle, from Old French triangle, from Latin triangulum, noun use of adjective triangulus (“three-cornered, having three angles”), from trēs (“three”) + angulus (“corner, angle”), equivalent to tri- +‎ angle.

• (UK) IPA^(key): /ˈtɹaɪəŋɡəl/, /ˈtɹaɪˌæŋɡəl/
• (US) enPR: trī'-ăng-gəl, IPA^(key): /ˈtɹaɪˌæŋɡəl/

• Audio (US)

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• Rhymes: -aɪæŋɡəl
• Hyphenation: tri‧an‧gle

triangle (plural triangles)

1. (geometry) A polygon with three sides and three angles.
   • 1981, William Irwin Thompson, The Time Falling Bodies Take to Light: Mythology, Sexuality and the Origins of Culture, London: Rider/Hutchinson & Co., page 22:

     The wedge-shaped character was the triangle, the archaic Paleolithic sign of the vulva; the pubic triangle was at the end of the phallic stylus.

2. (US, Canada) A set square.
3. (music) A percussion instrument made by forming a metal rod into a triangular shape which is open at one angle. It is suspended from a string and hit with a metal bar to make a resonant sound.
4. (cue sports) A triangular piece of equipment used for gathering the balls into the formation required by the game being played.
5. A love triangle.
   • 2009, Neil McDonald, Quadrant, November 2009, No. 461 (Volume LIII, Number 11), Quadrant Magazine Limited, page 104:

     One of the writers' most pleasing inventions was to treat the triangle love story as comedy.

6. (systemics) The structure of systems composed with three interrelated objects.
7. A draughtsman's square in the form of a right-angled triangle.
8. (historical, usually in the plural) A frame formed of three poles stuck in the ground and united at the top, to which people were bound when undergoing corporal punishment.
   • 1868, “The Week”, in The Nation‎, volume 6, number 149:

     But nothing is said as to what we are to do with the negro when we have cut him off from absolute dominion; we are not informed if we may spread him on the triangles as aforetime;

9. Any of various large papilionid butterflies of the genus Graphium.

   Synonym: bluebottle

10. (rail transport) A triangular formation of railway tracks, with a curve on at least one side.
    • 1961 March, ""Balmore"", “Driving and firing modern French steam locomotives”, in Trains Illustrated, page 147:

      After turning on the triangle at Jeumont, we set off light engine back to Aulnoye.

    Synonym: wye

• (polygon): threeside, trigon (rare)
• (love triangle): love triangle, menage à trois
• See also Thesaurus:triangle
• See also △ (symbol)

• Triangle on Wikipedia.Wikipedia
• Triangle (disambiguation) on Wikipedia.Wikipedia
• Triangle (instrument) on Wikipedia.Wikipedia

• INTEGRAL, alerting, altering, integral, relating, tanglier, teraglin

Borrowed from Latin triangulum.

• IPA^(key): (Central, Balearic) [tɾiˈaŋ.ɡlə]
• IPA^(key): (Valencian) [tɾiˈaŋ.ɡle]

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triangle m (plural triangles)

1. (geometry) triangle
2. (music) triangle

• triangular

• “triangle” in Diccionari de la llengua catalana, segona edició, Institut d’Estudis Catalans.
• “triangle”, in Gran Diccionari de la Llengua Catalana, Grup Enciclopèdia Catalana, 2024
• “triangle” in Diccionari normatiu valencià, Acadèmia Valenciana de la Llengua.
• “triangle” in Diccionari català-valencià-balear, Antoni Maria Alcover and Francesc de Borja Moll, 1962.

Borrowed from Latin triangulum. By surface analysis, tri- +‎ angle.

• IPA^(key): /tʁi.jɑ̃ɡl/

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triangle m (plural triangles)

1. (geometry) triangle (polygon)

   triangle équilatéral ― equilateral triangle

   triangle isocèle ― isosceles triangle

2. (music) triangle (percussion instrument)

• triangle amoureux
• triangle de sécurité
• triangulaire

• “triangle”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.

• intégral