Definition of triangle
1 : a polygon having three sides — compare spherical triangle
2a : 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
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Time Traveler for triangle
The first known use of triangle was in the 14th century
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