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