[poly.gon] n [LL polygonum, fr. Gk polygonon, fr. neut. of polygonos polygonal, fr. poly- + gonia angle--more at -gon] (1571) 1: a closed plane figure bounded by straight lines
2: a closed figure on a sphere bounded by arcs of great circles -- po.lyg.o.nal adj -- po.lyg.o.nal.ly adv