What is the Roman Theatre called?

The cavea was sometimes constructed on a small hill or slope in which stacked seating could be easily made in the tradition of the Greek theatres. The center of the cavea was hollowed out of a hill or slope, while the outer radian seats required structural support and solid retaining walls.

What is the ancient theater term for stage?

logeia

logeia: a speaking place, a stage). A high stage used by actors in Hellenistic theatres.