triangle

A triangle is a shape with three angles and three sides. (noun)

An example of something in the shape of a triangle is a piece of pizza.

See triangle in Webster's New World College Dictionary

noun

a geometric figure having three angles and three sides
any three-sided or three-cornered figure, area, object, part, etc.
a right-angled, flat, triangular instrument used in drawing geometric figures
a situation involving three persons, esp. when one person is having love affairs with two others
a musical percussion instrument consisting of a steel rod bent into a triangle with one angle open: it produces a high-pitched, tinkling sound when struck with a short steel rod

See triangle in American Heritage Dictionary 4

(trīˈăngˌgəl)

noun

a. The plane figure formed by connecting three points not in a straight line by straight line segments; a three-sided polygon.
b. Something shaped like such a figure: a triangle of land.
Any of various flat, three-sided drawing and drafting guides, used especially to draw straight lines at specific angles.
Music A percussion instrument consisting of a piece of metal in the shape of a triangle open at one angle.
A relationship involving three people, especially a ménage à trois.

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