An octahedron is a polyhedron with 8 faces. A regular octahedron, whose sides are all equilateral triangles, is one of the Platonic solids; it looks like two square pyramids with their square bases stuck together.

 

Cuboctahedron

 

Cuboctahedron.

 

A cuboctahedron is a polyhedron obtained by cutting the corners off a cube or an octahedron. It has 8 faces that are equilateral triangles and 6 faces that are squares.