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.