- 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 v&imacron;cennium, period of twenty years : Latin v&imacron;ci&emacron;ns, twenty times (from v&imacron;gint&imacron;, twenty; see vicenary) + Latin annus, year; see at- in Indo-European roots.