/seks'sen ten"euh ree, seks sen"tn er'ee/ or, esp. Brit. /-sen tee"neuh ree/ , adj., n., pl. sexcentenaries .
adj.
1. pertaining to 600 or a period of 600 years; marking the completion of 600 years.
n.
2. a 600th anniversary or its celebration.
[ 1770-80; SEX- + CENTENARY ]