Definition of pentahedron in US English:


nounPlural pentahedrons, Plural pentahedra

  • A solid figure with five plane faces.

    • ‘Then the pyramids are cut by silhouettes into a set of pentahedrons, which together constitute the centripetal pentahedron model of the visual hull.’
    • ‘You can also have an Egyptian pentahedron square-base pyramid.’
    • ‘Whereas the tetrahedron is composed of four triangles, the pyramid (or pentahedron), which looks a lot like it, is composed of four triangles and a square - the base.’


Late 18th century: from penta- ‘five’ + -hedron, on the pattern of words such as polyhedron.