n. | 1. | 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. |
| 2. | Any room adapted to the exhibition of any performances before an assembly, as public lectures, scholastic exercises, anatomical demonstrations, surgical operations, etc. |
| 3. | That which resembles a theater in form, use, or the like; a place rising by steps or gradations, like the seats of a theater. |
| 4. | A sphere or scheme of operation. |
| 5. | A place or region where great events are enacted; as, the theater of war. |