Webster's Revised Unabridged Dictionary · 1913

Auditorium

Auditorium ({not transcribed}) , noun

[L. See Auditory, n.]

1.
The part of a church, theater, or other public building, assigned to the audience.

In ancient churches the auditorium was the nave, where hearers stood to be instructed; in monasteries it was an apartment for the reception of strangers.

2.
a building, or a room within a building, containing a large open space for public gatherings, and often having a raised stage where speakers or presentations may be easily viewed by the audience.