Polyhedron rhymes with:
octahedron, tetrahedron, octahedron, tetrahedron, audran, cauldron, chadron, children, condron, excedrin, gendron, grandchildren, hendron, hydron, kindran, madron, octahedron, padron, philodendron, ravindran, rhododendron, schoolchildren, squadron, stepchildren, tetrahedron, vorndran, waldren, waldron