Definition of polyhedron in US English:


nounPlural polyhedra, Plural polyhedrons

  • A solid figure with many plane faces, typically more than six.

    • ‘The icosahedron is one of only five regular convex polyhedrons, the symmetric ‘Platonic solids’ that fascinated the ancient Greeks (the cube is another).’
    • ‘Plato believed that atoms have the shapes of regular polyhedra: cubes, tetrahedrons, octahedrons, and so on.’
    • ‘He submitted his first paper on this topic then, encouraged by Legendre and Malus, he submitted a further paper on polygons and polyhedra in 1812.’
    • ‘Kepler connected the planetary orbits with the five regular polyhedra, or Platonic solids.’
    • ‘For example, fair dice don't have to be in the shape of regular polyhedra, such as cubes, icosahedra, and so on.’


Late 16th century: from Greek poluedron, neuter (used as a noun) of poluedros ‘many-sided’.