triangular

American  

[trahy-ang-gyuh-ler] / traɪˈæŋ gyə lər /

adjective

1. pertaining to or having the form of a triangle; three-cornered.

2. having a triangle as base or cross section.

   a triangular prism.

3. comprising three parts or elements; triple.

4. pertaining to or involving a group of three, as three persons, parties, or things.

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triangular British  

/ traɪˌæŋɡjʊˈlærɪtɪ, traɪˈæŋɡjʊlə /

adjective

1. Also: trigonal.  of, shaped like, or relating to a triangle; having three corners or sides

2. of or involving three participants, pieces, or units

3. maths having a base shaped like a triangle

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Other Word Forms

• subtriangular adjective
• subtriangularity noun
• triangularity noun
• triangularly adverb

Etymology

Origin of triangular

1535–45; < Latin triangulāris, equivalent to triangul ( um ) triangle + -āris -ar ¹

Explanation

Anything that looks like a a shape with three sides and three angles is triangular. If you see a triangular fin in the ocean while you’re swimming, watch out! Shark! Start looking for triangular shapes and you'll begin to see them everywhere, from a triangular slice of pizza to a tortilla chip. Like triangle, triangular is rooted in the Latin tri-, "three," and angulus, "angle or corner." You'll also occasionally find this adjective describing things that involve three people, like a triangular relationship between three best friends.

Example Sentences

They are part of HS2's Delta junction, a complex triangular network of 13 viaducts, and will allow southbound trains to join the spur into Birmingham Curzon Street and the rolling stock depot at Washwood Heath.

From BBC • Apr. 16, 2026

The FAA also cordoned off a triangular zone south of Key West.

From Salon • Jan. 12, 2026

"During these drainages, extensive triangular fracture fields with cracks in the ice formed from 2019 onwards, which are shaped differently from all lake drainages I have seen so far," Humbert said.

From Science Daily • Jan. 5, 2026

O’Neill resolves the triangular conflict with a combination of religious fervor, metaphoric brooding and scabrous humor.

From Los Angeles Times • Dec. 15, 2025

The triangular shape of the boy leaning on the ledge gives stability to the painting, which helps to suspend the fleeting instant in time.

From "History of Art, Volume 1" by H.W. Janson

Related Words

• trilateral