Polygon
in geometry, a portion of a plane bounded on all sides by more than four limited straight lines. These lines are called sides of the polygon, and the points in which they meet are called vertices of the polygon. Polygons are classified according to the number of their sides or angles. Polygons having all their sides equal are called equilateral; those having all their angles equal are called equiangular. Polygons which are both equilateral and equiangular are called regular polygons. Similar polygons are to one another as the squares of their homologous sides. In fortification, the exterior polygon is the figure formed by lines connecting the angles of the bastion round the work. The interior polygon is the figure formed by lines connecting the centers of the bastions all round.
POLYGONACEÆ, buckwheats; an order of hypogynous exogens, alliance Silenales. Herbs, rarely shrubs. Distribution, world wide. Known genera 29, species 490. (Lindley.)