triangular

adjective

tri·​an·​gu·​lar trī-ˈaŋ-gyə-lər 

1

a

: of, relating to, or having the form of a triangle

a triangular plot of land

b

: having a triangular base or principal surface

a triangular table

a triangular pyramid

2

a(1)

: of, relating to, or involving three elements

a triangular agreement

(2)

of a military group : based primarily on three units

b

: of or relating to a love triangle

triangularity

(ˌ)trī-ˌaŋ-gyə-ˈler-ə-tē 

-ˈla-rə-tē

noun

triangularly

trī-ˈaŋ-gyə-lər-lē 

adverb

Examples of triangular in a Sentence

Recent Examples on the Web

The Academy itself is known for its mid-century modern architecture, and the interior of the Polaris, with its high lobby ceilings and exposed structural components mirrors the famed triangular arches of the Academy Chapel. —Larry Olmsted, Forbes.com, 26 Apr. 2025

The umbo has bristles that are the same color as the shell, with a triangular shape, researchers said. —Irene Wright, Miami Herald, 24 Apr. 2025

The structure will be the latest addition to Veteran’s Memorial Park, a half-acre triangular plot across the street from the Arlington Heights United Methodist Church. —Jaime Moore-Carrillo, Fort Worth Star-Telegram, 9 Apr. 2025

The hotel’s interior design, much of which was conceived by British designer Robert Angell, celebrates the hotel’s history and unusual triangular shape. —Angelina Villa-Clarke, Forbes, 20 Mar. 2025

Word History

Etymology

Middle English trianguler, from Late Latin triangularis, from Latin triangulum

First Known Use

14th century, in the meaning defined at sense 1a

Phrases Containing triangular

• triangular number

Rhymes for triangular

• quadrangular
• rectangular
• subangular
• angular
• subtriangular

Kids Definition

triangular

adjective

tri·​an·​gu·​lar trī-ˈaŋ-gyə-lər 

1

: of, relating to, or having the form of a triangle

2

: having a triangular base or principal surface

a triangular pyramid

Medical Definition

triangular

noun

tri·​an·​gu·​lar trī-ˈaŋ-gyə-lər 

: triquetral bone