amb-urbĭum, ii, n. [urbs],
the expiatory procession round the city of Rome , at which sacrifices were offered (v. the preced.); Serv. ad Verg. E. 3, 77; Paul. ex Fest. p. 17 Müll.: lustrata urbs, cantata carmina, amburbium celebratum, ambarvalia promissa, Vop. Aur. 20 (described in Luc. 1, 592 sq.).