orchestra

…large circular dancing floor (orchēstra in Greek) on which the action took place and in the centre of which was an altar to Dionysus; behind this, a scene-building and dressing room (skēne in Greek, whence “scene”), a low architectural facade to which painted scenery could be fitted, sometimes on…

…altar of Dionysus, called the orchestra. In the centre stood a platform with steps (bemata) leading to the altar (thymele). Nearby was the temple out of which the holy image would be carried on festival days so that the god could be present at the plays.