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

In America, scones are usually triangular, err on the crumbly and dense side, are loaded with mix-ins, and may be savory or sweet. —Karla Walsh, Better Homes & Gardens, 26 Feb. 2026

During wildlife surveys in 2022 and 2023 in eastern Thailand, a research team came across a small, nocturnal gecko with a triangular head and large, slightly protruding eyes. —Ryan Brennan, Kansas City Star, 25 Feb. 2026

New At just over 7 inches long, this gecko is compact, with a triangular head and large, slightly protruding brown eyes. —Ryan Brennan, Charlotte Observer, 25 Feb. 2026

Letchinger said the $800 million first phase will create more than 700 units on a triangular patch bounded by Kingsbury Street, Cortland Avenue and Southport Avenue. —Brian J. Rogal, Chicago Tribune, 15 Jan. 2026

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