What is the term for the area designated for the audience, typically filled with seats?

The term for the area designated for the audience, typically filled with seats, is "auditorium." This space is specifically designed to accommodate viewers during performances, lectures, or presentations. It is often equipped with seating arrangements that allow for optimal sightlines to the stage, as well as sound systems and lighting conducive to enhancing the overall viewing experience.

In contrast, the stage refers to the area where the performers present their work, and backstage encompasses the area that is not visible to the audience, where actors and crew prepare for performances. The balcony is a specific feature of some auditoriums that provides additional seating on an upper level, but it does not encompass the entire audience area, which is why "auditorium" is the most accurate term for describing the audience's designated space.