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

Recently cut ponytail; a triangular necklace of brown-and-yellow beads; a face moving from baby fat to bone; a desire for adventure without the self-confidence or ability. —Literary Hub, 21 Nov. 2025

Audio is delivered through a 2.1 channel high-fidelity speaker system with a triangular acoustic chamber, designed to match the high intensity of your sessions with equally immersive sound. —Jason Phillips, USA Today, 6 Nov. 2025

The applicator holds a good amount of product without becoming gloppy, and the triangular tip is perfect for lining my outer corners and defining the Cupid's bow. —Sarah Han, Allure, 31 Oct. 2025

Thousands of people reported witnessing a triangular formation of lights moving silently across the sky. —Tiffany Acosta, AZCentral.com, 28 Oct. 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