disphenoid adjective 2noun 1forms 1 adjective2 •Of or pertaining to a wedge-shaped crystal form of the tetragonal or orthorhombic system. •Of or pertaining to a crystal form bounded by eight scalene triangles arranged in pairs, constituting a tetragonal scalenohedron. noun1 •A non-regular tetrahedron whose four faces are congruent acute-angled triangles.The mineral chalcopyrite commonly crystallizes in disphenoids that are very difficult to distinguish from tetrahedrons. — 1949 formsdisphenoids
