centennial

Short definition from Wiktionary

Adjective

1. 1
   Relating to, or associated with, the commemoration of an event that happened a hundred years before.
2. 2
   Happening once in a hundred years.
3. 3
   Lasting or aged a hundred years.

Noun

1. 1
   The hundredth anniversary of an event or happening.

Proper noun

1. 1
   A city in Colorado.
2. 2
   A census-designated place in Wyoming.