triangle
n. countablen. a shape with three straight sides and three corners. It is also a small metal musical instrument that you hit with a stick.
n. a polygon with three vertices and three edges. In a musical context, a percussion instrument consisting of a steel rod bent into a three-sided shape, open at one corner.
The children learned how to draw a triangle in school.
The percussionist waited for the conductor's signal before striking the triangle during the final movement.
In Euclidean geometry, the sum of the interior angles of a triangle always equals one hundred and eighty degrees, a fundamental principle used in various engineering calculations.
From triangle; in North Carolina from being a triangular region.
In music, it is usually preceded by the definite article 'the' when referring to the orchestral part.