triangle

noun tri·an·gle \ ˈtrī-ˌaŋ-gəl \

Updated on: 9 May 2018

Definition of triangle

1 : a polygon having three sides — compare spherical triangle

2 a : a percussion instrument consisting of a rod of steel bent into the form of a triangle open at one angle and sounded by striking with a small metal rod

b : a drafting instrument consisting of a thin flat right-angled triangle of wood or plastic with acute angles of 45 degrees or of 30 degrees and 60 degrees

3 : a situation in which one member of a couple is involved in a love affair with a third person

See triangle defined for English-language learners

See triangle defined for kids

Examples of triangle in a Sentence

She cut the sandwiches into triangles.

Recent Examples of triangle from the Web

The Promise This 2016 historical drama sets a love triangle against the backdrop of the systematic extermination of 1.5 million Armenians by the Ottoman government from 1915 to 1917.

— ed stockly, latimes.com, "Saturday's TV highlights and weekend talk shows: The Dodgers take on the Padres in Monterrey, Mexico," 4 May 2018
Back in March, PEOPLE reported on a hawk love triangle playing out in a New York City park.

— saryn chorney, ajc, "'Unheard of' polygamous owl family consists of two moms, one dad and pair of owlets," 3 May 2018
The desperate act came not because of a romantic triangle, but because of Seinn's long-term relationship with Mangaccat.

— CBS News, "Workplace crush turns deadly at San Francisco airport," 2 May 2018
The first 200-page draft was more of a coming-of-age movie than a comedy, centering on a love triangle between Danny, Irish club employee Maggie (Sarah Holcomb) and fellow caddie Tony (Scott Colomby).

— patrick ryan, USA TODAY, "'Caddyshack': 5 wild things we learn about the Bill Murray comedy in new tell-all book," 24 Apr. 2018
Various comic contrivances ensue before this messy love triangle gets instantly resolved.

— john von rhein, chicagotribune.com, "Chicago Opera Theater brings flair to comic, serious Donizetti one-acters," 15 Apr. 2018
Bachie's project involved cleaning the numerous plaques and statues in Berea's town center and painting the Civil War cannon on the city's triangle.

— rich heileman, cleveland.com, "Joining the Eagles: Bachie, Miu attain scouting's top rank: Around The Town," 30 Mar. 2018
The charges of battery come after a confusing love triangle went sour.

— lukas mikelionis, Fox News, "Neo-Nazi leader who sued Trump now faces domestic violence charges after love triangle," 15 Mar. 2018
The Tesfaye-Gomez-Bieber love triangle appears to be a big inspiration for The Weeknd's My Dear Melancholy album, and fans seem to agree.

— erica gonzales, Harper's BAZAAR, "Selena Gomez Seems Completley Unfazed by The Weeknd's Songs About Her," 30 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'triangle.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Illustration of triangle

Origin and Etymology of triangle

Middle English, from Anglo-French, from Latin triangulum, from neuter of triangulus triangular, from tri- + angulus angle

NEW! Time Traveler

First Known Use: 14th century

in the meaning defined at sense 1

See Words from the same year

TRIANGLE Defined for English Language Learners

triangle

noun

Definition of triangle for English Language Learners

: a shape that is made up of three lines and three angles
: something that is shaped like a triangle
: a musical instrument that is made of a steel rod bent into the shape of a triangle and that you play by hitting with a metal rod

TRIANGLE Defined for Kids

triangle

noun tri·an·gle \ ˈtrī-ˌaŋ-gəl \

Definition of triangle for Students

1 : a flat geometric figure that has three sides and three angles

2 : something that has three sides and three angles

a triangle of land

3 : a musical instrument made of a steel rod bent in the shape of a triangle with one open angle

Medical Dictionary

triangle

noun tri·an·gle \ ˈtrī-ˌaŋ-gəl \

medical Definition of triangle

: a three-sided region or space and especially an anatomical one — see anterior triangle, carotid triangle, femoral triangle, posterior triangle, suboccipital triangle