arena

/əˈɹiːnə/
noun
  1. 1

    An enclosed area, often outdoor, for the presentation of sporting events (sports arena) or other spectacular events; earthen area, often oval, specifically for rodeos (North America) or circular area for bullfights (especially Hispanic America).

    A large crowd filled the seats of the arena.

  2. 2

    The building housing such an area; specifically, a very large, often round building, often topped with a dome, designated for indoor sporting or other major events, such as concerts.

    The arena is grey with white beams.

  3. 3

    The sand-covered centre of an amphitheatre where contests were held in Ancient Rome.

    The gladiators entered the arena.

  4. 4

    A realm in which events take place; an area of interest, study, behaviour, etc.

    The company was a player in the maritime insurance arena.

Source: https://en.wiktionary.org/wiki/arena