Cone

Solid bounded by a conical and a plane surface, or by a conical and two parallel plane surfaces. The fixed point of the conical surface is the vertex; the parts on each side of it are the upper and the lower nappes; the plane surfaces are upper and lower bases. Ordinarily but one nappe and one base are considered. Cones are cla ified as circular, elliptical, etc., according to their conical surfaces. They are right or oblique, as the axis makes a right or oblique angle with the plane of the base.