triangular vs triangle

triangular is not a noun while triangle is a noun.

Word	Noun	Adjective	Verb	Adverb
triangular	No	Yes	No	No
triangle	Yes	No	No	No

triangular (noun)	triangle (noun)
	a percussion instrument consisting of a metal bar bent in the shape of an open triangle
	any of various triangular drafting instruments used to draw straight lines at specified angles
	a three-sided polygon
	something approximating the shape of a triangle

triangular (adjective)	triangle (adjective)
having three angles; forming or shaped like a triangle
having three sides