quincentenary(n = noun.time) quincentennial - the 500th anniversary (or the celebration of it);
is a kind of anniversary, day of remembrance
quincentenary(a = adj.pert) quincentennial - of or relating to a 500th anniversary; "the quincentennial celebration of the founding of the city"
quincentenary, n. & adj.
--n. (pl. -ies)
1 a five-hundredth anniversary.
2 a festival marking this.
--adj. of this anniversary.
Derivative:
quincentennial adj. & n.
Etymology:
irreg. f. L quinque five + CENTENARY