The term "flies" is used because these galleries are usually located high up in the theater, near the ceiling, and may be accessed by a series of stairs or ladders. From this elevated position, audience members can have an unobstructed view of the stage, though they may be farther away from the action than those seated in the orchestra or main seating area.
In some theaters, the flies may also be used as a storage area for props, sets, and other equipment that can be lowered or raised onto the stage as needed during a performance. Additionally, the flies may serve as a place for technicians to operate lighting and sound equipment, as well as for actors to make quick costume changes or exits during a performance.