the oval space in the center of a Roman amphitheater for gladiatorial combats or other performances.

a central stage, ring, area, or the like, used for sports or other forms of entertainment, surrounded by seats for spectators

a boxing arena; a circus arena.

a building housing an arena.

a field of conflict, activity, or endeavor

the arena of politics.

noun

amphitheatre , boards , bowl * , circus , coliseum , course , diamond , field , gridiron , ground , gym , gymnasium , hippodrome , ice , park , pit , platform , ring , rink , square , stadium , stage , battlefield , battleground , domain , province , realm , scene , sector , sphere , territory , theatre , bailiwick , circle , department , orbit , subject , terrain , world , amphitheater , bowl , court , oval , stade