a building, part of a building, or outdoor area for housing dramatic presentations, stage entertainments, or motion-picture shows.
the audience at a theatrical or motion-picture performance: The theater wept.
a theatrical or acting company.
a room or hall, fitted with tiers of seats rising like steps, used for lectures, surgical demonstrations, etc.: Students crowded into the operating theater.
dramatic performances as a branch of art; the drama: an actress devoted to the theater.
dramatic works collectively, as of literature, a nation, or an author (often prec. by the): the theater of Ibsen.
the quality or effectiveness of dramatic performance: good theater; bad theater; pure theater.
a place of action; field of operations.
a natural formation of land rising by steps or gradations.