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