Amphitheatre vs. Theatre

Amphitheatre and Theatre Definitions
Amphitheatre
An open, outdoor theatre (which may be a theatre in the round, or have a stage with seating on only one side), especially one from the classical period of ancient Greece or Rome, or a modern venue of similar design.
Ancient Roman amphitheatres were mostly oval or circular in plan, with seating tiers that surrounded the central performance area, like a modern open-air stadium.
Theatre
Variant of theater.
Amphitheatre
(geology) A natural formation of a similar shape, where a steep mountain or slope a particular rock formation forms a partial or compete bowl, especially one used as a performance space (and possibly modified by carving out seats, etc) because the slopes naturally amplify or echo sound.
Theatre
Alternative spelling of theater
Amphitheatre
A sloping gallery with seats for spectators (as in an operating room or theater)
Theatre
A cinema; movie theatre.
ADVERTISEMENT
Amphitheatre
An oval large stadium with tiers of seats; an arena in which contests and spectacles are held
Theatre
A building where theatrical performances or motion-picture shows can be presented;
The house was full
Theatre
The art of writing and producing plays
Theatre
A region in which active military operations are in progress;
The army was in the field awaiting action
He served in the Vietnam theater for three years