An edifice in which dramatic performances or spectacles are exhibited for the amusement of spectators; anciently uncovered, except the stage, but in modern times roofed.
- A building, room, or outdoor structure for the presentation of plays, films, or other dramatic performances.
- A room with tiers of seats used for lectures or demonstrations: an operating theater at a medical school.
- Dramatic literature or its performance; drama: the theater of Shakespeare and Marlowe.
- The milieu of actors and playwrights.
- The quality or effectiveness of a theatrical production: good theater; awful theater.
- Dramatic material or the use of such material: "His summation was a great piece of courtroom theater” ( Ron Rosenbaum).
- The audience assembled for a dramatic performance.
- A place that is the setting for dramatic events.
- A large geographic area in which military operations are coordinated: the European theater during World War II.