Lewis Short
(adjective) : dormītōrĭus, a, um, id.
* Of or for sleeping (post-Aug.): cubiculum,Plin. Ep. 5, 6, 21: so, membrum,id. ib. 2, 17, 9; and subst., dormitorium, ii, n., a sleeping-room, dormitory, Plin. 30, 6, 17, § 51.
Charlton T. Lewis, Charles Short, A Latin Dictionary