A realm in which events take place; an area of interest, study, behaviour, etc.
The sand-covered centre of an amphitheatre where contests were held in Ancient Rome.
An enclosed area, often outdoor, for the presentation of sporting events (sports arena) or other spectacular events; earthen area, often oval, specifically for rodeos (North America) or circular area for bullfights (especially Hispanic America).
The building housing such an area; specifically, a very large, often round building, often topped with a dome, designated for indoor sporting or other major events, such as concerts.
The area in which opponents or opposing ideas meet.
The region or line along which opposing armies engage in combat.