structure,
construction a thing constructed; a complex entity constructed of many parts; "the structure consisted of a series of arches"; "she wore her hair in an amazing construction of whirls and ribbons"
An arena is an enclosed area, often circular or oval-shaped, designed to showcase theater, musical performances, or sporting events. It is composed of a large open space surrounded on most or all sides by tiered seating for spectators. The key feature of an arena is that the event space is the lowest point, allowing for maximum visibility.
OmegaWiki Dictionary
Ω
arena A particular environment or walk of life.
arena A large structure for open-air sports or entertainments.