八面体
Octahedron \Oc`ta*he"dron\, n. [Gr.?, fr. ? eight-side; ? (for ? eight) + ? seat, base, from ? to sit.] (Geom.) A solid bounded by eight faces. The regular octahedron is contained by eight equal equilateral triangles.
octahedron n : any polyhedron having eight plane faces [also: {octahedra} (pl)]