hexoctahedron

from The Century Dictionary.

• noun A crystalline form belonging to the isometric system and contained under forty-eight equal triangular faces. Also called adamantoid, because it is a common form of the diamond. Also hexakisoctahedron.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Geom.) A solid having forty-eight equal triangular faces.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun geometry A solid with forty-eight equal triangular faces.