quadrangular

from WordNet (r) 3.0 (2006)

quadrangular
    adj 1: of or relating to or shaped like a quadrangle

from The Collaborative International Dictionary of English v.0.48

Quadrangular \Quad*ran"gu*lar\, a. [Cf. F. quadrangulaire.]
   Having four angles, and consequently four sides; tetragonal.
   -- {Quad*ran"gu*lar*ly}, adv.
   [1913 Webster]