Relating to or consisting of a hundred; relating to a period of a hundred years; recurring once in every hundred years: as, a centenary festival or celebration.n. pl. centenaries (-riz).n. The space of a hundred years.n. What I call by this name has grown up in the last centenary — a word I may use to signify the hundred years now ending. De Morgan, in Correspondent of Oct. 28, 1865.n. The commemoration or celebration of the hundredth anniversary of any event, as the birth of a great man: as, the centenary of Burns; the centenary of the Constitution of the United States.n. A centenarian.