Circus

1. (Roman Antiq.) A level oblong space surrounded on three sides by seats of wood, earth, or stone, rising in tiers one above another, and divided lengthwise through the middle by a barrier around which the track or course was laid out. It was used for chariot races, games, and public shows.
2. A circular inclosure for the exhibition of feats of horsemanship, acrobatic displays, etc. Also, the company of performers, with their equipage.
3. Circuit; space; inclosure.

The Circus Maximus at Rome could contain more than 100,000 spectators.