triangle

American  

[trahy-ang-guhl] / ˈtraɪˌæŋ gəl /

noun

• triangles
  plural

1. a closed plane figure having three sides and three angles.

2. a flat triangular piece, usually of plastic, with straight edges, used in connection with a T square for drawing perpendicular lines, geometric figures, etc.

3. any three-cornered or three-sided figure, object, or piece.

   a triangle of land.

4. a musical percussion instrument that consists of a steel triangle, open at one corner, that is struck with a steel rod.

5. a group of three; triad.

6. a situation involving three persons, especially one in which two of them are in love with the third.

7. Astronomy. Triangle, the constellation Triangulum.

---

triangle British  

/ ˈtraɪˌæŋɡəl /

noun

1. geometry a three-sided polygon that can be classified by angle, as in an acute triangle, or by side, as in an equilateral triangle. Sum of interior angles: 180°; area: 1/ 2 base × height

2. any object shaped like a triangle

3. any situation involving three parties or points of view See also eternal triangle

4. music a percussion instrument consisting of a sonorous metal bar bent into a triangular shape, beaten with a metal stick

5. a group of three

---

triangle Scientific  

/ trī′ăng′gəl /

1. A closed geometric figure consisting of three sides.

---

triangle Idioms  

1. see eternal triangle.

---

Other Word Forms

Derived Forms

• triangled
  adjective

Inflected Forms

Nouns

• triangles
  plural

---

Etymology

Origin of triangle

First recorded in 1350–1400; Middle English, from Latin triangulum, noun use of neuter of triangulus “three-cornered”, see tri-, angle ¹

---

Explanation

A triangle is a flat shape with three sides and three angles, like a slice of pizza, a yield sign, or the Greek letter delta. If you look carefully, you'll notice triangles all around you! A triangle is a polygon, which is a closed shape like a square or a hexagon, but a triangle has only three sides. Wedges of pie and some tortilla chips are shaped like triangles. If you invite your crush to a movie and they bring a date, you have yourself a love triangle. Triangle comes from the Latin word triangulus, "three-cornered" or "having three angles," from the roots tri-, "three," and angulus, "angle or corner."

Example Sentences

See Examples For:

triangle triangles

Walmart WMT 1.47%increase; up pointing triangle has actively worked with OpenAI and Google to try to boost traffic via AI tools, which the retailer’s U.S.

From The Wall Street Journal ● Oct. 16, 2026

Schneider Electric SU -2.42%decrease; down pointing triangle lifted its annual targets for the second time this year after data-center orders kept flowing in, boosting sales for the third quarter.

From The Wall Street Journal ● Oct. 16, 2026

Natural-gas exporter Venture Global VG -4.12%decrease; down pointing triangle is joining the race to provide power to the AI boom, aiming to build gas-fired generation at its facilities to supply electricity to data centers.

From The Wall Street Journal ● Oct. 15, 2026

Kimberly-Clark KMB 1.14%increase; up pointing triangle forecast a decline in third-quarter sales and backed its outlook for the year, following a social-media firestorm in China over the company’s diapers this past summer.

From The Wall Street Journal ● Oct. 15, 2026

For a quick second Neel pictured himself breaking through the triangle of pursuers, leaping into the nauka, and rowing himself and the cub away from danger.

From "Tiger Boy" by Mitali Perkins

Small triangles would behave almost exactly as Euclid predicted, and short parallel paths would not noticeably converge.

From Science Daily ● Sep. 28, 2026

They do not do this in fixed zones but look to create these triangles when they feel like the moment is right.

From BBC ● Sep. 13, 2026

Another young adult drama debuting later this year is “Minimum Wage,” which focuses on teens managing part-time jobs and love triangles.

From Los Angeles Times ● Aug. 14, 2026

The other part of Tuchel's system that was continually emphasised was use of wide triangles to create chances, with the 52-year-old reluctant to see his side build through the centre.

From BBC ● Jul. 16, 2026

Mother even made toast and cut the pieces into little triangles and put on lots of butter.

From "Miracles on Maple Hill" by Virginia Sorensen

Random Word

Spin the wheel and learn a new word!

---

Related Words

• adultery
• affair
• courtship
• dalliance
• devotion
• fling
• flirtation
• infidelity
• involvement
• liaison
• love
• passion
• relationship
• tryst

---