Source : Webster's Revised Unabridged Dictionary (1913)

Centenary \Cen"te*na*ry\, a. [L. centenarius, fr. centum a
   hundred.]
   1. Relating to, or consisting of, a hundred.

   2. Occurring once in every hundred years; centennial.
      ``Centenary solemnities.'' --Fuller.

Centenary \Cen"te*na*ry\, n.; pl. {Centenaries}.
   1. The aggregate of a hundred single things; specifically, a
      century. ``Every centenary of years.'' --Hakewill.

   2. A commemoration or celebration of an event which occurred
      a hundred years before.

Source : WordNet®

centenary
     adj : of or relating to or completing a period of 100 years;
           "centennial celebration" [syn: {centennial}]
     n : the 100th anniversary (or the celebration of it) [syn: {centennial}]