deltohedron

from The Century Dictionary.

• noun In crystallography, a hemihedral isometric solid bounded by twelve faces, each a quadrilateral. The corresponding holohedral form is a trigonal trisoctahedron.

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

• noun (Crystallog.) A solid bounded by twelve quadrilateral faces. It is a hemihedral form of the isometric system, allied to the tetrahedron.

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

• noun The dual polyhedron of a regular n-sided antiprism.