Trisoctahedron \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.