Source : Webster's Revised Unabridged Dictionary (1913)

Octahedral \Oc`ta*he"dral\, a. [See {Octahedron}.]
   Having eight faces or sides; of, pertaining to, or formed in,
   octahedrons; as, octahedral cleavage.

   {Octahedral borax} (Chem.), borax obtained from a saturated
      solution in octahedral crystals, which contain five
      molecules of water of crystallization; distinguished from
      common or prismatic borax.

   {Octahedral iron ore} (Min.), magnetite.