A dodecahedron is a 12-sided, three-dimensional figure with 20 vertices, 30 edges, 120 diagonals and five sides per face. Each vertex is the meeting point of three edges, and each face is the shape of a regular pentagon.
A dodecahedron is one of the five Platonic solids, which are regular polyhedrons with congruent faces that have contain regular polygons and feature the same number of faces meeting at each vertex. These five solids include a tetrahedron, cube, octahedron, dodecahedron and icosahedron. A tetrahedron has four faces, a cube has six faces, an octahedron contains eight faces, and an icosahedron has 20 faces. The Platonic solids are named for the Greek philosopher Plato.