bĭennĭum, ii, n. [bis-annus],
a period or space of two years , two years : jam biennium est, cum, etc., Plaut. Merc. 3, 1, 35: intra tempus biennii, Col. 3, 9, 6: hoc factum est ferme abhinc biennium, Plaut. Bacch. 3, 2, 4 (imitated by Ps.- Plaut. Merc. prol. 12): biennium ibi perpetuum misera illum tuli, Ter. Hec. 87; Caes. B. G. 1, 3; Cic. Phil. 5, 3, 7; Liv. 5, 14, 2: biennium provinciam obtinuit, Cic. Verr. 2, 3, 93, § 216; 2, 4, 30, § 67: lex usum et auctoritatem fundi jubet esse biennium, id. Caecin. 19, 54; Quint. Ep. ad Tryph. 1; id. Inst. 1, 12, 9: biennio postquam abii, Plaut. Bacch. 2, 1, 1: comitia biennio habita, Liv. 5, 14, 2: matres, quae biennio durant, Plin. 11, 21, 24, § 73; Suet. Galb. 7: consulatum biennio post ultro petiit, id. Aug. 26: intra tempus bienni, Col. R. R. 3, 9, 6: intra biennium, Quint. 1, 2, 9: ultra biennium, Tac. A. 1, 1.