Lewis & Short

annĭversārĭus, a, um, adj. [annusverto], that returns, happens, is used, etc., every year, returning or renewed annually, annual, yearly: sacra, Cic. Verr. 2, 4, 39: Ecce solemnitas Domini est in Silo anniversaria, Vulg. Jud. 21, 19: festi dies, Cic. Verr. 2, 4, 48 fin.: (caeli) vicissitudines, the changes of the seasons of the year, id. N. D. 2, 38, 97; Varr. R. R. 1, 16, 4: arma, Liv. 4, 45; so, hostes, Flor. 1, 12: valetudines, Suet. Aug. 81: pervigilium, id. Galb. 4 al.
Adv.: annĭversārĭē, annually, Aug. Ep. 118 fin.