Synonyms for Arena:

n.

civic center, aquarium, bowling alley, art-house, bullring, cinema, club. scene, bag, terrain, department, territory. •arena (noun)
dominion, auditorium, province, circus, courtyard, bailiwick, ring, ground, area, precinct, gallery, beat, enclosure, hippodrome, amphitheater, hall, orbit, circuit, field, campus, sphere, locale, battlefield, room, stage, setting, realm, region, turf, circle, stadium, gymnasium, theater, domain, battle-ground, colosseum, bowl, pen, scene of action.
•department (noun)
precinct.
•field (noun)
gridiron, platform, baseball field, square, coliseum, pit, course, gym, park, boxing ring, football field.
•place (noun)
habitat, place, forum, floor, spot, station, location, site.
•region (noun)
region.
•state (noun)
field, area, orbit, domain, sphere.

Other synonyms:

bullring, civic center, cinema, aquarium, art-house, bowling alley. department, gym. bag, terrain. club, territory, scene. •stadium
coliseum, stadium.
•Other relevant words:
gridiron, gym, platform, club, coliseum, park, pit, boxing ring, scene, department, territory, art-house, square, bowl, bullring, course, orbit, aquarium, bag, terrain, stadium, sphere, scene of action.

Usage examples for arena

1. " I had forgotten the report that he would fight in the arena – Warrior of the Dawn by Howard Carleton Browne

2. It has as its proper arena the political field. – Leading Articles on Various Subjects by Hugh Miller