Source : Webster's Revised Unabridged Dictionary (1913)

Dodecahedron \Do*dec`a*he"dron\, n. [Gr. ?; ? twelve + ? seat,
   bottom, base: cf. F. dod['e]ca[`e]dre.] (Geom. & Crystallog.)
   A solid having twelve faces.

   Note: The regular dodecahedron is bounded by twelve equal and
         regular pentagons; the pyritohedron (see
         {Pyritohedron}) is related to it; the rhombic
         dodecahedron is bounded by twelve equal rhombic faces.

Source : WordNet®

dodecahedron
     n : any polyhedron having twelve plane faces