octahedral \oc`ta*he"dral\ ([o^]k`t[.a]*h[=e]"dral), a. [See {octahedron}.] Having eight faces or sides; of, pertaining to, or formed in, octahedrons; as, octahedral cleavage; an octahedral crystal. [1913 Webster] {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. [1913 Webster]