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quā̆drĭennĭum, ii, n. [quadriennis], a space or period of four years (class.), Cic. Caecin. 7, 19; id. Opt. Gen. 7, 22; id. Sen. 4, 10; id. Verr. 2, 3, 18, § 47; Flor. 2, 6.