cĭsĭum, ii, n.,
a light two-wheeled vehicle , a cabriolet (vehiculi biroti genus, Non. p. 86, 30), Cic. Phil. 2, 31, 77; id. Rosc. Am. 7, 19; Vitr. 10, 1, 6; Aus. Ep. 8, 6; gen. cisi, Verg. Cat. 8, 3 Burm.; cf. Becker, Gall. 3, p. 9; Dict. of Antiq.
cisium ī, n a light two-wheeled vehicle, cabriolet. ...
An Elementary Latin Dictionary