TETRAHEDRAL

Etymology

Adjective

tetrahedral (not comparable)

in the shape of a tetrahedron

having four faces, four apices and six edges

Source: Wiktionary

Tet`ra*he"dral, a. Etym: [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.

Source: Webster’s Unabridged Dictionary 1913 Edition