Old Greek Theater is a term used to describe the ancient theaters of Greece, which were used for performances of plays, music, and other forms of entertainment. The two most common types of Old Greek Theater are the ODEON and the Odeum. The ODEON was a large theater, typically built in a semi-circular shape, with seating for thousands of spectators. The Odeum was a smaller theater, usually rectangular in shape, with seating for hundreds of spectators. Both types of theaters were used for performances of plays, music, and other forms of entertainment.