Pronunciation: (thē'u-tur, thēu'-),[key] —n. 1. a building, part of a building, or outdoor area for housing dramatic presentations, stage entertainments, or motion-picture shows.
2. the audience at a theatrical or motion-picture performance: The theater wept. 3. a theatrical or acting company.
4. a room or hall, fitted with tiers of seats rising like steps, used for lectures, surgical demonstrations, etc.: Students crowded into the operating theater. 5. the theater,dramatic performances as a branch of art; the drama: an actress devoted to the theater. 6. dramatic works collectively, as of literature, a nation, or an author (often prec. by the): the theater of Ibsen. 7. the quality or effectiveness of dramatic performance: good theater; bad theater; pure theater. 8. a place of action; field of operations.
9. a natural formation of land rising by steps or gradations. Also,theatre.