tetragon n 1: a four-sided polygon [syn: {quadrilateral}, {quadrangle}, {tetragon}]
Tetragon \Tet"ra*gon\, n. [L. tetragonum, Gr. tetra`gwnon; te`tra- (see {Tetra-}) + gwni`a corner, angle: cf. F. t['e]tragone.] 1. (Geom.) A plane figure having four sides and angles; a quadrangle, as a square, a rhombus, etc. [1913 Webster] 2. (Astrol.) An aspect of two planets with regard to the earth when they are distant from each other ninety degrees, or the fourth of a circle. --Hutton. [1913 Webster]