triangular
Americanadjective
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Also: trigonal. of, shaped like, or relating to a triangle; having three corners or sides
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of or involving three participants, pieces, or units
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maths having a base shaped like a triangle
Other Word Forms
Etymology
Origin of triangular
1535–45; < Latin triangulāris, equivalent to triangul ( um ) triangle + -āris -ar 1
Explanation
Anything that looks like a a shape with three sides and three angles is triangular. If you see a triangular fin in the ocean while you’re swimming, watch out! Shark! Start looking for triangular shapes and you'll begin to see them everywhere, from a triangular slice of pizza to a tortilla chip. Like triangle, triangular is rooted in the Latin tri-, "three," and angulus, "angle or corner." You'll also occasionally find this adjective describing things that involve three people, like a triangular relationship between three best friends.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The Flatiron Building - with its unique triangular shape, narrow prow, ornamental columns and intricate decorative details - has been one of the most recognisable structures in New York City for more than a century.
From BBC ● Jul. 26, 2026
The table’s triangular, gently curved glass plane reads like the calm surface of a pool, beneath which the legs summon a cascade of associations: sea life, bones, waterfowl, twisted roots.
From The Wall Street Journal ● Jul. 1, 2026
The insect can be identified by its flat triangular head, large eyes and clear wings.
From Los Angeles Times ● Jun. 11, 2026
The spaces between the fingers resemble the triangular basins created as the crust extends.
From Science Daily ● Jun. 4, 2026
Swiftly Milton lifted its triangular green lid and laid the briefcase inside.
From "Middlesex: A Novel" by Jeffrey Eugenides
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
