vigintennial

English

Etymology

From viginti- (“twenty”) +‎ -ennial (“yearly”), from Latin vīgintī (“twenty”) and -enniālis, from annus (“year”) + -is (“forming compound adjectives”) + -ālis (“-al: forming adjectives”).

Adjective

vigintennial (not comparable)

1. (rare) Synonym of vicennial, occurring every twenty years.

References

• “vigintennial, adj.”, in OED Online ⁠, Oxford: Oxford University Press, launched 2000.