Lewis Short
quādrĭdŭum | quātrĭd- (noun N) : (), , quattuor-dies
* A space of four days, four days (class.): in hoc triduo aut quadriduo,Plaut. Pers. 1, 1, 37; so Cato, R. R. 65, 2; 113, 2; Cic. Verr. 2, 4, 3, § 6; id. Tusc. 5, 4, 11; 4, 38, 82; Liv. 3, 3; Curt. 4, 7, 15: quadriduo quo haec gesta sunt,four days after,Cic. Rosc. Am. 7, 20: quadriduum per vastas solitudines absumptum est,Plin. 6, 22, 24, § 86.
Charlton T. Lewis, Charles Short, A Latin Dictionary