Obs. [ad. late L. biennāl-e (sc. officium), neuter of biennālis of two years (see next).] The saying of masses for a departed soul during the period of two years.
1362. Langl., P. Pl., A. VIII. 156. Bienals [v.r. biennales, byennals] and Trienals and Busschopes lettres.
