{ Theater, Theatre } (?), n. [F. théâtre, L. theatrum, Gr. &unr_;, fr. &unr_; to see, view; cf. Skr. dhyā to meditate, think. Cf. Theory.] 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.
[1913 Webster]

2. Any room adapted to the exhibition of any performances before an assembly, as public lectures, scholastic exercises, anatomical demonstrations, surgical operations, etc.
[1913 Webster]

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. Burns.
[1913 Webster]

Shade above shade, a woody theater
Of stateliest view. Milton.
[1913 Webster]

4. A sphere or scheme of operation. [Obs.]
[1913 Webster]

For if a man can be partaker of God's theater, he shall likewise be partaker of God's rest. Bacon.
[1913 Webster]

5. A place or region where great events are enacted; as, the theater of war.
[1913 Webster]