Meaning of “triangle” - Learner’s Dictionary

triangle

noun [ C ] uk us /ˈtraɪæŋɡl/
SHAPE

B2 a flat shape with three sides

MUSICAL INSTRUMENT

a small musical instrument made of a piece of metal with three sides which you hit with a metal bar

triangular uk us /traɪˈæŋɡjələr/ adjective

shaped like a triangle

(Definition of “triangle” from the Cambridge Learner’s Dictionary © Cambridge University Press)