arena

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An enclosed area for the presentation of sports events and spectacles.
2. n. A building housing such an area
3. n. A place or scene where forces contend or events unfold: withdrew from the political arena; the world as an arena of moral conflict.
4. n. The area in the center of an ancient Roman amphitheater where contests and other spectacles were held.

Century Dictionary and Cyclopedia

1. n. The inclosed space in the central part of the Roman amphitheaters, in which the combats of gladiators or wild beasts took place. It was usually covered with sand or sawdust, to prevent the gladiators from slipping and to absorb the blood, and, for the protection of the spectators from the beasts, was surrounded by a high wall, which was often surmounted by a strong granting.
2. n. Figuratively, the scene or theater of exertion or contest of any kind: as, the arena of war or of debate.
3. n. In pathology, sand or gravel in the kidneys.
4. n. In architecture, the main area of a temple, church, or other building.
5. n. Are not.

Wiktionary

1. n. An enclosed area, often outdoor, for the presentation of sporting events (sports arena) or other spectacular events; earthen area, often oval, specifically for rodeos (N. America) or circular area for bullfights (especially Hispanic America).
2. n. The building housing such an area.
3. n. The sand-covered centre of an amphitheatre where contests were held.
4. n. A realm in which important events unfold.

GNU Webster's 1913

1. n. (Rom. Antiq.) The area in the central part of an amphitheater, in which the gladiators fought and other shows were exhibited; -- so called because it was covered with sand.
2. n. Any place of public contest or exertion; any sphere of action
3. n. (Med.) “Sand” or “gravel” in the kidneys.

WordNet 3.0

1. n. the central area of an ancient Roman amphitheater where contests and spectacles were held; especially an area that was strewn with sand
2. n. a playing field where sports events take place
3. n. a particular environment or walk of life
4. n. a large structure for open-air sports or entertainments