The Collaborative International Dictionary of English v.0.48:

Bicentennial \Bi`cen*ten"ni*al\, a. [Pref. bi- + centennial.]
   1. Consisting of two hundred years.
      [1913 Webster]

   2. Occurring every two hundred years.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Bicentennial \Bi`cen*ten"ni*al\, n.
   The two hundredth year or anniversary, or its celebration.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bicentennial
    adj 1: of or relating to or completing a period of 200 years;
           "bicentennial celebration" [syn: bicentennial,
           bicentenary]
    n 1: the 200th anniversary (or the celebration of it) [syn:
         bicentennial, bicentenary]

Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "bicentennial":
   C, anniversary, annual holiday, bicentenary, biennial, birthday,
   bissextile day, cental, centare, centenarian, centenary,
   centennial, centennium, centigram, centimeter, centipede,
   centistere, centred, centref, centrev, centumvir, centumvirate,
   centurion, century, commemoration, cwt, decennial, diamond jubilee,
   golden wedding anniversary, gross, hecatomb, holy days, hundred,
   hundredweight, immovable feast, jubilee, leap year, long hundred,
   name day, natal day, octennial, one C, quadrennial,
   quasquicentennial, quincentenary, quincentennial, quinquennial,
   septennial, sesquicentenary, sesquicentennial, sextennial,
   silver wedding anniversary, tercentenary, tercentennial,
   tricennial, triennial, wedding anniversary