Lewis & Short

cēnātōrĭus (caen- and coen-), a, um, adj. [cena], of or pertaining to dinner, or to the table (only post-Aug.): fames, Sid. Ep. 2, 9 fin.: vestis, Capitol. Max. Jun. 4.
Subst.: cēnātōrĭa, ōrum, n., dinner dress, Petr. 21, 5; Mart. 10, 87, 12; 14, 135 tit.; Dig. 32, 2, 34.
In sing. also cēnātōrĭ-um, ii, n., = cenatio, a dining-room, Inscr. Orell. 2493; cf. cenatorium, οἴκημα, δειπνητήριον, Gloss. Cyr.