May 2016 - You might think a vomitorium must have something to do with barfing, and those stories about Romans eating too much and then making themselves barf so they could eat more. But a vomitorium is really much more boring than that.
A vomitorium is called that because it's a thing that something comes out of. When you puke, food comes out of your mouth. But in Roman architecture, a vomitorium is a hallway in a Roman theater or an amphitheater that people come out of - the hallway that you walk through to get to your seat, or to get out of the amphitheater after the show.
You can see vomitoria for yourself at any big sports stadium - though we don't call them that anymore.
Make This Model Roman Amphitheatre, by Iain Ashman (1995).
Roman Architecture, by Frank Sear (1983). The standard college textbook.
The Roman Amphitheatre: From its Origins to the Colosseum, by Katherine Welch (2004). By a specialist, for specialists.