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

These ottoman-style seats are different from the rest, featuring a large footrest rather than the standard small, triangular ledge, although preselecting one comes with a $100 price tag. —Scott Campbell, Travel + Leisure, 6 Apr. 2025

The triangular designs feel playful but not overwhelming in spaces that lean bohemian or eclectic. —Nora Taylor, Architectural Digest, 4 Apr. 2025

Rectangular heads are great for covering large surface areas while triangular heads are good for corners and small areas. —Bestreviews, Chicago Tribune, 20 Mar. 2025

The triangular end sections of the floor plan, between the floor edges and occupants' heads and feet, are meant for storing gear, and four interior pockets provide space for smaller belongings. —New Atlas, 15 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