Tetragonal

a.	1.	(Geom.) Of or pertaining to a tetragon; having four angles or sides; thus, the square, the parallelogram, the rhombus, and the trapezium are tetragonal fingers.
	2.	(Bot.) Having four prominent longitudinal angles.
	3.	(Crystallog.) Designating, or belonging to, a certain system of crystallization; dimetric. See Tetragonal system, under Crystallization.

Adj.

1.

tetragonal - of or relating to or shaped like a quadrilateral

quadrangle, quadrilateral, tetragon