Tet′ra‐he″dral (?), a. [See Tetrahedron.] 1. Having, or composed of, four sides.
2. (Crystallog.) (a) Having the form of the regular tetrahedron. (b) Pertaining or related to a tetrahedron, or to the system of hemihedral forms to which the tetrahedron belongs.
Tetrahedral angle(Geom.), a solid angle bounded or inclosed by four plane angles.