Octahedron

The octahedron has eight equilateral triangles as faces. It has six vertices and twelve edges. At each vertex four triangles are meeting.

The octahedron is one of the five Platonic solids. A Platonic solid is a regular, convex polyhedron. The faces of a Platonic solid are congruent, regular polygons. At each vertex the same number of faces are meeting, see also model 411.

The five Platonic solids are Tetrahedron, Hexahedron (Cube), Octahedron, Dodecahedron and Icosahedron.