An arena is a circular or oval shaped public space (akin to a classical amphitheatre), designed to showcase theater, musical performances, or sporting events. It is composed of a large open space surrounded on all sides by raised, usually tiered, seats or benches for spectators. The key feature of an arena is that the event space is the lowest point, allowing for maximum visibility. Usually, an arena is designed to accommodate a very large number of spectators, such as New York City's Madison Square Garden or Pasadena's Rose Bowl.

The term "arena" is also used loosely to refer to any event or type of event which either literally or metaphorically takes place in such a location--- often with the specific intent of comparing an idea to a sporting event, such as "the arena of war" or "the arena of love."

In the United States, the term 'arena' generally refers specifically to indoor stadia.

See also: List of indoor arenas

There are also the following other meanings for the word Arena:

• Arena, Wisconsin
• Arena (town), Wisconsin
• Arena Township, Minnesota
• Arena (web browser)
• Verona Arena, Roman amphitheatre in Verona, Italy
• Arena (colosseum) in Pula, Croatia
• Arena (active countermeasures system) - Russian active protection system for tanks
• Arena (band)
• Arena (album) and Arena (An Absurd Notion), works by Duran Duran
• ARENA (Salvadoran political party)
• Arena (television)
• Arena (computer game)
• Arena (magazine)
• Arena (swimwear)