Tetrahedral
Pronunciation : Tet`ra*he"dral
Part of Speech : a.
Etymology : [See Tetrahedron.]
Definition : 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.
Source : Webster's Unabridged Dictionary, 1913