say it: TRAHY-ang-guhl
triangle is a noun meaning "a three-sided polygon". It carries 5 recorded senses.
a three-sided polygon
something approximating the shape of a triangle
“the coastline of Chile and Argentina and Brazil forms two legs of a triangle”
a small northern constellation near Perseus between Andromeda and Aries
any of various triangular drafting instruments used to draw straight lines at specified angles
a percussion instrument consisting of a metal bar bent in the shape of an open triangle
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for triangle come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.