triangle

(noun) a three-sided polygon. Synonyms: trigon, trilateral.

(noun) something approximating the shape of a triangle. Example: "The coastline of chile and argentina and brazil forms two legs of a triangle."

(noun) a small northern constellation near Perseus between Andromeda and Aries. Synonyms: Triangulum, Triangle.

(noun) any of various triangular drafting instruments used to draw straight lines at specified angles.

(noun) a percussion instrument consisting of a metal bar bent in the shape of an open triangle.