A place or building, consisting of a stage and seating, in which an audience gathers to watch plays, musical performances, public ceremonies, and so on.
2
A region where a particular action takes place; a specific field of action, usually with reference to war.
His grandfather was in the Pacific theater during the war.
3
A lecture theatre.
4
An operating theatre or locale for human experimentation.
This man is about to die, get him into theater at once!