tri·​an·​gle | \ ˈtrī-ˌaŋ-gəl How to pronounce triangle (audio) \

Definition of triangle

1 : a polygon having three sides — compare spherical triangle
2a : 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

Illustration of triangle

Illustration of triangle

triangle 1: 1 equilateral, 2 acute, 3 obtuse, 4 scalene, 5 isosceles, 6 right triangle

Examples of triangle in a Sentence

She cut the sandwiches into triangles.
Recent Examples on the Web The shopping bags have a distinctive triangular cut-out to create a handle—the triangle is now a signature branding motif on clothes, belt buckles, and other accessories. Jessica Iredale, Town & Country, "Why Bottega Veneta Will Eventually Return to Social Media," 11 Jan. 2021 And Lue is using this because Leonard expressed a desire to perform in the triangle. Broderick Turner Staff Writer, Los Angeles Times, "Clippers to employ triangle offense sets for Kawhi Leonard," 20 Dec. 2020 Another target date is Oyster Ridge Free Music Festival, a bluegrass event also held the last weekend of July, also in the triangle. Maria Halkias, Dallas News, "J.C. Penney has found a home for the larger-than-life James Cash Penney statue," 15 Dec. 2020 The actress stars in Lawrence Michael Levine’s Black Bear, an indie drama of startling intensity, as a filmmaker-actress staying in a lake house, struggling to create (and hitting the booze) as she becomes embroiled in a toxic love triangle. Mary Sollosi,, "With Black Bear, Aubrey Plaza has become the new queen of indies," 17 Nov. 2020 In the glass corner, a triangle table with benches makes a breakfast area. Judy Rose, Detroit Free Press, "$3M White Lake glass house is a window on the world," 27 Dec. 2020 In one case filed at the end of November, the government is seeking to seize a triangle of land smaller than 2 acres in the county. Perla Trevizo, ProPublica, "The Trump Administration Keeps Awarding Border Wall Contracts but Doesn’t Own the Land to Build On," 25 Dec. 2020 Lift the point on the opposite side of the moistened edges, and fold the wonton over the filling into a triangle, working out any air bubbles from the center and pressing the edges to seal. Washington Post, "Vegetarian wontons are a delight to eat in this light, fragrant soup," 20 Dec. 2020 These funky triangle clips will help your giftee pin back their hair in a more stylish way. Courtney Campbell, USA TODAY, "30 great gifts under $5 that won't end up in the trash," 11 Dec. 2020

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.

See More

First Known Use of triangle

14th century, in the meaning defined at sense 1

History and Etymology for triangle

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

Keep scrolling for more

Learn More about triangle

Time Traveler for triangle

Time Traveler

The first known use of triangle was in the 14th century

See more words from the same century

Statistics for triangle

Last Updated

22 Jan 2021

Cite this Entry

“Triangle.” Dictionary, Merriam-Webster, Accessed 23 Jan. 2021.

Keep scrolling for more

More Definitions for triangle


How to pronounce triangle (audio)

English Language Learners Definition of triangle

: 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


tri·​an·​gle | \ ˈtrī-ˌaŋ-gəl How to pronounce triangle (audio) \

Kids Definition of triangle

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


tri·​an·​gle | \ ˈtrī-ˌaŋ-gəl How to pronounce triangle (audio) \

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

Keep scrolling for more

More from Merriam-Webster on triangle

Nglish: Translation of triangle for Spanish Speakers

Britannica English: Translation of triangle for Arabic Speakers Encyclopedia article about triangle

Comments on triangle

What made you want to look up triangle? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Slippery Words Quiz—Changing with the Times

  • ducreux self portrait yawning
  • What is an earlier meaning of nice?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

 AlphaBear 2

Spell words. Make bears.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!