Source : Webster's Revised Unabridged Dictionary (1913)

Bicentennial \Bi`cen*ten"ni*al\, a. [Pref. bi- + centennial.]
   1. Consisting of two hundred years.

   2. Occurring every two hundred years.

Bicentennial \Bi`cen*ten"ni*al\, n.
   The two hundredth year or anniversary, or its celebration.

Source : WordNet®

bicentennial
     adj : of or relating to or completing a period of 200 years;
           "bicentennial celebration" [syn: {bicentenary}]
     n : the 200th anniversary (or the celebration of it) [syn: {bicentenary}]