Cross Section A cross section of a solid is a plane figure obtained by the intersection of that solid with a plane. The cross section of an While the cross section of a sphere is always a disk, the cross section of a cube may be a square, hexagon, or other shape. SEE ALSO: Axonometry, Cavalieri's Principle, Conic Section, Cylindric Section, Ellipsoidal Section, Inner Quermass, Lamina, Plane, Projection, Radon Transform, Spheric Section, Spheroidal Section, Spiric Section, Stereology Toric Section Weisstein, Eric W. "Cross Section." From MathWorld--A Wolfram Web Cross Section in the Solids of Known Cross Section Solids of Known Cross Section Solids of Known Cross Section