like a triangle in shape 三角的；三角形的 involving three people or groups 涉及三人的；三组的；三方面的 a triangular contest in an election 竞选中三位候选人的角逐
Word Originmid 16th cent.: from late Latin triangularis, from Latin triangulum, neuter of triangulus ‘three-cornered’ (see tri- and the noun angle).