Source : Webster's Revised Unabridged Dictionary (1913)

Hexagonal \Hex*ag"o*nal\, a. [Cf. F. hexagonal.]
   Having six sides and six angles; six-sided.

   {Hexagonal system}. (Crystal.) See under {Crystallization}.

Source : WordNet®

hexagonal
     adj : having six sides or divided into hexagons [syn: {hexangular}]