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 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 fancy vivid blue-green diamond is triangular in shape and "the size of the nail on your smallest finger" according to Fawcett.
From Barron's ● May 13, 2026
You will tape each end of the tail to where it matches the width of the triangular sections to make a connected long loop.
From Los Angeles Times ● May 3, 2026
They are part of HS2's Delta junction, a complex triangular network of 13 viaducts, and will allow southbound trains to join the spur into Birmingham Curzon Street and the rolling stock depot at Washwood Heath.
From BBC ● Apr. 16, 2026
They had broad triangular heads, like the prairie rattlers back in Montana, but their bodies were muck-colored and ominously plump.
From "Hoot" by Carl Hiaasen
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.
