·adj Having four prominent longitudinal angles.
II. Tetragonal ·adj Designating, or belonging to, a certain system of crystallization; dimetric. ·see Tetragonal system, under Crystallization.
III. Tetragonal ·adj Of or pertaining to a tetragon; having four angles or sides; thus, the square, the parallelogram, the rhombus, and the trapezium are tetragonal fingers.