What do we call the lowest tier of seating in a theatre that is positioned at the same height as the stage?

The term "stalls" refers specifically to the lowest seating area in a theater, which is typically at the same level as the stage. This positioning allows for an immersive viewing experience, where audience members can feel closely connected to the performance. Stalls are often considered premium seating because of their proximity to the action, making them desirable seats among theatergoers.

While other terms like "orchestra level" might initially sound applicable in specific contexts, stalls are the universally recognized term for this seating area in most theaters. "Low seats" and "auditorium floor" are not standard terminologies used within theater language and do not specifically denote the seating area that corresponds directly to the level of the stage. Thus, stalls is the correct answer, as it accurately identifies the designated seating arrangement in question.