REGULAR BODY, called also Platonic Body, is a body or solid comprehended by like, equal, and regular, plane figures, and whose solid angles are all equal.
The plane figures by which the solid is contained are the faces of the solid; and the lines of the plane figures are the edges, or linear sides of the solid.
There are only five regular solids, viz.
The tetrahedron, or regular triangular pyramid, having four triangular faces;
The hexahedron, or cube, having six square faces;
The octahedron, having eight triangular faces;
The dodecahedron, having twelve pentagonal faces;
The icosahedron, having twenty triangular faces.
Besides these five, there can be no other regular bodies in nature. See PLATONIC Body, Suppl.