Cen*ten"ni*al (?), a. [L. centum a hundred + annus year.] 1. Relating to, or associated with, the commemoration of an event that happened a hundred years before; as, a centennial ode.

2. Happening once in a hundred years; as, centennial jubilee; a centennial celebration.

3. Lasting or aged a hundred years.

That opened through long lines
Of sacred ilex and centennial pines.
Longfellow.

Cen*ten"ni*al, n. The celebration of the hundredth anniversary of any event; a centenary. [U. S.]

• the 100th anniversary of an event or happening.