Definition of: theater

(thē′ə·tər) noun
1. A building especially adapted to dramatic, operatic, or spectacular representations; playhouse.
2. The theatrical world and everything relating to it.
3. A room or hall arranged with seats that rise as they recede from a platform, especially adapted to lectures, surgical demonstrations, etc.
4. Any place of semicircular form with seats rising by easy gradations.
5. Any place or region that is the scene of events: a theater of operations in war. Also the′a·tre. [<OF theatre <Gk. theatron <theasthai behold]