If an auditorium is a place where the audience sits, a ‘vomitorium’ should be a room where people vomit. Unfortunately, this is not the case. The word comes from the world of ‘theatre’. A ‘vomitorium’ was the passageway that people used to get to their seats in an amphitheatre. These passages were situated below or behind an individual’s seat, and they enabled the members of the audience to enter and exit the theatre very quickly. I understand that the ‘vomitoria’ in the Colosseum in Rome were so well designed that it was possible for 50,000 people to enter or exit the place in 15 minutes.
The word ‘vomitorium’ comes from the Latin ‘vomitus’, meaning ‘to vomit’. What is the connection? When you vomit, the contents of your stomach are thrown out. The ‘vomitorium’ disgorged or forced out the ‘contents’ of the theatre — the people inside!