The Collaborative International Dictionary of English v.0.48:

Tetrahexahedron \Tet`ra*hex`a*he"dron\, n. [Tetra- +
   hexahedron.] (Crystallog.)
   A solid in the isometric system, bounded by twenty-four equal
   triangular faces, four corresponding to each face of the
   cube.
   [1913 Webster]