polyedron

Noun

polyhedron (plural polyhedra or polyhedrons)

1. A solid figure with many flat faces and straight edges.
   • Of the convex polyhedra with regular faces, the only ones that have tetrahedral, octahedral, or icosahedral symmetry are the Platonic and Archimedean solids.1966, Norman W. Johnson, “Convex Polyhedra with Regular Faces”, in Canadian Journal of Mathematics, volume XVIII, number I, Toronto: University of Toronto Press, page 181
2. A polyscope, or multiplying glass.
3. A stage in the growth of Hydrodictyon, when the resting spore breaks up into several megazoospores that put out horn-like appendages; these polyhedra break up into zoospores.