: a percussion instrument consisting of a rod of steel bent into the form of a triangle open at one angle and sounded by striking with a small metal rod
b
: a drafting instrument consisting of a thin flat right-angled triangle of wood or plastic with acute angles of 45 degrees or of 30 degrees and 60 degrees
3
: a situation in which one member of a couple is involved in a love affair with a third person
Illustration of triangle
1 equilateral
2 acute
3 obtuse
4 scalene
5 isosceles
6 right triangle
Examples of triangle in a Sentence
She cut the sandwiches into triangles.
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Her symbol for it is a hexagram, the down triangle blue, the up one yellow.—Walker Mimms, New York Times, 15 May 2025 Hauling assist is provided by a 750-W motor mounted in the middle of the rear triangles, which peaks at 1,400 watts – with a responsive torque sensor onboard to help with a smooth take-off.—Paul Ridden
may 11, New Atlas, 11 May 2025 This outdoor version puts a fun spin on the classic game, as players toss bean bags to rotate the triangles on the board to show either X or O. Whoever gets three in a row wins.—Katrina Cossey, Parents, 1 May 2025 Straightforward shapes like circles and triangles become intricate and complex in his treatments, enticing viewers and demanding to be examined closely.—Stephanie Rudig, Smithsonian Magazine, 30 Apr. 2025 See All Example Sentences for triangle
Word History
Etymology
Middle English, from Anglo-French, from Latin triangulum, from neuter of triangulus triangular, from tri- + angulus angle
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