dodecahedron

n. polyhedron having twelve plane faces (Geometry)

A dodecahedron is any polyhedron with twelve faces, but usually a regular dodecahedron is meant: a Platonic solid composed of twelve regular pentagonal faces, with three meeting at each vertex. It has twenty (20) vertices and thirty (30) edges. Its dual polyhedron is the icosahedron. To the ancient Greeks, the dodecahedron was a symbol of the universe.
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Noun
1. any polyhedron having twelve plane faces
(hypernym) polyhedron

(n.)
A solid having twelve faces.
  

Dodecahedron The regular solid with twelve pentagonal faces, or the rhombic dodecahedron of crystallography; in The Secret Doctrine usually a synonym of dodecad, a group of twelve or the number twelve. Plato in Phaedo says that the world, if seen from above, would look like a ball covered with twelve differently colored pieces of leather. The Pythagoreans investigated regular solids, attaching great importance to them as symbols, including the regular dodecahedron which was a symbol of the universe in full manifestation.