The meaning of auditorium / ballroom in dream | Dream Interpretation
Vision: Dancing in a ballroom: a fun-filled social event will lift your spirits. Seeing a large auditorium: you will have to deal with many people. Participating at a conference: you will be asked to solve a conflict.
Depth Psychology: Since an auditorium is a place where people meet, the dream implies that you are looking for contact, diversion, and companionship. Was the meeting fun or somber?