1911 Encyclopædia Britannica/Centenary

CENTENARY (from Lat. centenarius, of or belonging to a hundred, from centeni, distributive of centum, hundred), a space of a hundred years, and particularly the celebration of an event on the lapse of a hundred years, a centennial anniversary. The word “centennial” (from Lat. centennis, from centum, and annus, a year), though usually an adjective as in “the Centennial State,” the name given to Colorado on its admission to statehood in 1876, is also used as a synonym of centenary.