\Tris*oc`ta*he"dron\, n. [Gr. ? thrice + FE.
octahedron.] (Crystallog.)
A solid of the isometric system bounded by twenty-four equal
faces, three corresponding to each face of an octahedron.
{Tetragonal trisoctahedron}, a trisoctahedron each face of
   which is a quadrilateral; called also {trapezohedron} and
   {icositetrahedron}.
{Trigonal trisoctahedron}, a trisoctahedron each face of
   which is an isosceles triangle.