|Origin:||triangulum, from tri- ( TRI-) + angulus 'angle'|
a flat shape with three straight sides and three angles
something that is shaped like a triangle:
a triangle of land
a musical instrument made of metal bent into the shape of a triangle. You hit it with a metal stick to make a ringing sound.
4 American EnglishHM
a flat plastic object with three sides that has one angle of 90° and is used for drawing angles [= set-square British English]