Lewis & Short

proscaenĭum (proscēn-), ii, n., = προσκήνιον.

  1. I. The place before the scene where the actors appeared, the proscenium; also, in gen., the stage, Plaut. Am. prol. 91; id. Truc. prol. 10, id. Poen. prol. 17: veteres ineunt proscaenia ludi, Verg. G. 2, 381: theatrum et proscaenium ad Apollinis locavit, Liv. 40, 51; Vitr. 5, 6; Suet. Ner. 12: proscaenii contabulatio, App. Flor. 4, p. 359, 1.
  2. II. Transf., a theatre (post-class.), Claud. Laud. Stil. 2, 403.