pentagonal

from WordNet (r) 3.0 (2006)

pentagonal
    adj 1: of or relating to or shaped like a pentagon [syn:
           {pentangular}, {pentagonal}]

from The Collaborative International Dictionary of English v.0.48

Pentagonal \Pen*tag"o*nal\, a. [Cf. F. pentagonal, pentagone, L.
   pentagonus, pentagonius, Gr. ?.]
   Having five corners or angles.
   [1913 Webster]

   {Pentagonal dodecahedron}. See {Dodecahedron}, and
      {Pyritohedron}.
      [1913 Webster]