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

Its central group of stars is arranged into rough rows that form a generally triangular shape, suggesting an old-fashioned beehive. —Joe Rao, Space.com, 18 Aug. 2025

Once, ships had carried slaves across the Atlantic as part of a triangular trade in captives and commodities that connected the international élite to sadistic violence in Africa and the Americas. —Daniel Immerwahr, New Yorker, 18 Aug. 2025

And Antonio closes the runway with a full-length pink puffy coat made out of triangular flags and a sheer dress made out of transparent vinyl bubbles that barely covers his model’s ass. —Roxana Hadadi, Vulture, 15 Aug. 2025

All reports of the sightings described three red or white lights in a triangular pattern that moved in unison, hovered for up to 30 minutes and made no audible sound. —Kori Rumore, Chicago Tribune, 14 Aug. 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