vicennalsEtymologyFrom Latin vīcennālia, from vīcennis (“20-year”) + -ālia (“-alia: forming festival names”), from vīciēs (“twenty times”) + annus (“year”) + -is (“forming compound adjectives”).vicennals means synonym of vicennalia: the festival and religious ritual held on the 20th anniversary of a Roman emperor's reign. Lexicurio rates it Sui generis — a strength score of 100 out of 100.nounSynonym of vicennalia: the festival and religious ritual held on the 20th anniversary of a Roman emperor's reign.