Octangular

from WordNet (r) 3.0 (2006)

octangular
    adj 1: of or relating to or shaped like an octagon [syn:
           {octangular}, {octagonal}]

from The Collaborative International Dictionary of English v.0.48

Octangular \Oc*tan"gu*lar\, a. [L. octangulus eight-cornered;
   octo eight + angulus angle.]
   Having eight angles; eight-angled. -- {Oc*tan"gu*lar*ness},
   n.
   [1913 Webster]