(a.) Having three sides; being three-sided; as, a trilateral triangle.

bifacial bilateral cuneate cuneated cuneiform deltoid dihedral flanked handed lateral many-sided multilateral one-sided oxygonal polyhedral quadrilateral sided tetrahedral three-cornered three-dimensional three-footed three-pronged three-sided triangular triangulate triarch trichotomous tricorn tricornered tricuspid trident tridental trifid triflorate triflorous trifurcate trigonal trigonoid trigrammatic trihedral trimerous triparted tripartite tripodic triquetral triquetrous trisected two-sided unilateral