noun, plural oc·ta·he·drons, oc·ta·he·dra [ok-tuh-hee-druh] /ˌɒk təˈhi drə/.
Examples from the Web for octahedron
The other piece of money in circulation was octahedron in shape or form.Memoirs of Orange Jacobs|Orange Jacobs
Both "octahedron / octahedral" and "octohedron / octohedral" occur and have not been changed.A Guide to the Mount's Bay and the Land's End|John Ayrton Paris
Its crystalline forms are very numerous, and are referrible to the octahedron, and the pyramidal prism.A Dictionary of Arts, Manufactures and Mines|Andrew Ure
That for the tetrahedron has 12 for its order, for the cube (or octahedron) 24, and for the icosahedron (or dodecahedron) 60.
A cube may be inscribed in an octahedron, its vertices being at the centers of the faces of the octahedron.The Teaching of Geometry|David Eugene Smith