postscenium
/ˌpəʊs(t)ˈsiːnɪəm/(also postscaenium) Classical Theatre
noun
A part of an ancient Greek or Roman theatre behind the stage, where props could be stored and to which the actors retired.
Origin
Early 18th century; earliest use found in Ephraim Chambers (?1680–1740), encyclopaedist. From classical Latin postscaenium from post- + scaena + -ium, after proscaenium.