- happening every twenty years
- lasting twenty years
Origin of vicennialLate Latin vicennialis from Classical Latin vicennium, period of twenty years from vicies, twenty times + annus, year (see annual)
- Happening once every 20 years.
- Existing or lasting for 20 years.
Origin of vicennialFrom Late Latin vīcennium period of twenty years Latin vīciēns twenty times ( from vīgintī twenty ; see vicenary . )Latin annus year ; see at- in Indo-European roots.