trilateral
Noun

A threesided polygon (synset 113901977)
hypernym: polygon, polygonal shape  a closed plane figure bounded by straight sideshyponym:
 acute triangle, acuteangled triangle  a triangle whose interior angles are all acute
 equiangular triangle, equilateral triangle  a threesided regular polygon
 isosceles triangle  a triangle with two equal sides
 oblique triangle  a triangle that contains no right angle
 obtuse triangle, obtuseangled triangle  a triangle that contains an obtuse interior angle
 right triangle, rightangled triangle  a triangle with one right angle
 scalene triangle  a triangle with no two sides of equal length
 cuneus, wedge, wedge shape  any shape that is triangular in cross section
Adjective

Involving three parties (synset 301952784)
similar: mutual, reciprocal  concerning each of two or more persons or things; especially given or done in return

Having three sides (synset 300241439)
similar: manysided, multilateral  having many parts or sidessynonym: threesided, triangular
Other Searches
 Rhyme: Dillfrog, RhymeZone
 Definition: Wiktionary, Dictionary.com, Wikipedia, MerriamWebster, WordNet
 Imagery: Google, Flickr, Bing