triangular
From Longman Dictionary of Contemporary EnglishRelated topics: Shapes, patternstriangulartri‧an‧gu‧lar /traɪˈæŋɡjələ $ -ər/ ●○○ adjective 1 CFshaped like a triangle2 COMPETITIONinvolving three people or teams a triangular sporting competitionExamples from the Corpustriangular• The dorsal arm plates are triangular and nearly contiguous.• On the night stand was a translucent orb atop a triangular clock.• a triangular relationship• Now I saw why, when viewed from the side, the album had such a strange, triangular shape.• The dorsal arm plates are bell shaped or triangular with a convex distal edge and are separated.