Definition of "vicennial" in English

adjective

1. Occurring once every twenty years.

2. Lasting for twenty years.

noun

1. A twenty-year period

2. A twentieth anniversary, particularly

   • Among the well established anniversaries celebrated by Chautauqua classes from year to year are the vicennials. A strong sense of comradeship is developed among members who come to Chautauqua twenty years after graduation...