Source : Webster's Revised Unabridged Dictionary (1913)

Dihexagonal \Di`hex*ag"o*nal\, a. [Pref. di- + hexagonal.]
   (a) Consisting of two hexagonal parts united; thus, a
       dihexagonal pyramid is composed of two hexagonal pyramids
       placed base to base.
   (b) Having twelve similar faces; as, a dihexagonal prism.