Theater

From Memory Alpha, the free Star Trek reference

Theater

Podium

The theater is a performance space found aboard certain Federation starships, with a stage and seating for a live audience. The theater can be used to show plays as well as musical performances. The Constitution-class USS Enterprise and the Galaxy-class USS Enterprise-D both had theaters. (TOS: "The Conscience of the King", TNG: "Sarek", "The Nth Degree", "Frame of Mind")

For the theater room as it appeared on Sarek, the Ten Forward stage was used. The theater in The Conscience of the King was a redress of the Engineering set.

On smaller starships, the mess hall may be converted into an impromptu movie theater, or a simulation of such a theater could be recreated on a holodeck. (ENT: "Dear Doctor", "Cold Front", VOY: "Repression")