triangle meaning and definition

TRIANGLE noun

Definition of triangle (noun)

1. a three-sided polygon
   • synonyms: trigon, trilateral
2. something approximating the shape of a triangle
   • "the coastline of Chile and Argentina and Brazil forms two legs of a triangle"
3. a small northern constellation near Perseus between Andromeda and Aries
   • synonyms: Triangulum
4. any of various triangular drafting instruments used to draw straight lines at specified angles
5. a percussion instrument consisting of a metal bar bent in the shape of an open triangle