triangular
tri.an.gu.lar \tri--'an-gy*-l*r\ \(.)tri--.an-gy*-'lar-*t-e-\
\tri--'an-gy*-l*r-le-\ aj [LL triangularis, fr. L triangulum] 1a: of,
relating to, or having the form of a triangle {~ plot of l and} 1b: having
a triangular base or principal surface {~ table ~ pyramid} 1a1: of,
relating to, or involving three elements of a military group 1a2: based
primarily on three units {~ division} 1b: of or relating to a love
triangle {a ~ love affair} - tri.an.gu.lar.i.ty n
Webster's English Dictionary