1. [n]  the 100th anniversary
2. [adj]  of or relating to or completing a period of 100 years; "centennial celebration"

CENTENARY is a 9 letter word that starts with C.

1. \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.
   
   

2. \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.