Definition of triangles:
(n) :
(geometry) A polygon with three sides and three angles.
(n) :
(music) A percussion instrument made by forming a metal rod into a triangular shape which is open at one angle. It is suspended from a string and hit with a metal bar to make a resonant sound.
(n) :
(US, Canada) A set square.
(n) :
(billiards) A triangular piece of equipment used for gathering the balls into the formation required by the game being played.
(n) :
A love triangle.
(n) :
(systemics) The structure of systems composed with three interrelated objects.