theater [3]
Establishment built to present plays, shows, dance performances, concerts and so forth.
balcony 
Area of the house located above the mezzanine.
seat 
Armchair used to watch a performance.
side 
row 
Series of seats the same distance from the stage.
center 
box 
Small partitioned room that seats two or three people.
mezzanine 
The floor above the parterre of the house.
parterre 
The first floor of the house.