proscenium (n.) Look up proscenium at Dictionary.com
c.1600, "stage of an ancient theater," from Latin proscaenium, from Greek proskenion "the space in front of the scenery," also "entrance of a tent," from pro "in front" (see pro-) + skene "stage, tent, booth" (see scene). Modern sense of "space between the curtain and the orchestra" is attested from 1807.