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 a landscape park in western Poland, remote sensing equipment discovered long, triangular formations below the surface, according to a July 9 Facebook post from the Team of Landscape Parks of the Greater Poland Voivodeship. —Irene Wright july 14, Miami Herald, 14 July 2025

Last August, the campus debuted an open-air music venue, the Geode, comprising four triangular structures that reflect the music played within them as audiences take in views of the Beartooth Mountains. —AFAR Media, 14 July 2025

The triangular bandana slides onto his collar with ease and is made from a stretchy, evaporative fabric that stays cool for hours. —Ali Faccenda, People.com, 11 July 2025

Kids love building houses, castles, vehicles, and whatever else occurs to them with these triangular and square magnetic tiles. —Simon Hill, Wired News, 11 July 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