Semicentennial \Sem`i*cen*ten"ni*al\, a. Of or pertaining to half of a century, or a period of fifty years; as, a semicentennial commemoration. Semicentennial \Sem`i*cen*ten"ni*al\, n. A fiftieth anniversary.
semicentennial adj : of or relating to or marking the 50th anniversary [syn: {semicentenary}] n : the 50th anniversary (or the celebration of it) [syn: {semicentenary}]