vīcennālis, e, adj. [vicennium], of twenty years, every twenty years (postclass.).
I Adj. : votis vicennalibus, Num. Alex. Sev. ap. Eckhel. D. N. V. 7, p. 275.—
II Subst.: vīcennālĭa , ĭum, n., a festival on the twentieth anniversary of an emperor's reign , Lact. Mort. Pers. 17.