What is a amphitheater

 Usually an amphitheatre is outdoors, but sometimes the same kind of seating arrangement indoors, as for basketball or hockey games, is also called an amphitheatre. Some amphitheatres were constructed by nature, not built by man; these are places where steep hills rise in a circle, so that the audience can sit on the hillsides and look down on the entertainment in the centre.

The most famous amphitheatre of all time was the Colosseum, about which there is a separate article. Today, an amphitheatre is not a real "theatre," because plays are not put on there, but the first amphitheatres, built thousands of years ago, were for plays. The ancient Greeks built them, and in the centre there were two stages, back to back, with plays on both stages at the same time. Wherever a person sat, he could see one stage or the other. In the Greek language, amphi- means "both," so the word meant "both theatres