Vomitorium

A vomitorium is a passage situated below or behind a tier of seats in an amphitheatre or a stadium, through which big crowds can exit rapidly at the end of a performance. They can also be pathways for actors to enter and leave stage. The Latin word "vomitorium", plural "vomitoria", derives from the verb "vomō, vomere", "to spew forth". In ancient Roman architecture, "vomitoria" were designed to provide rapid egress for large crowds at amphitheatres and stadia, as they do in modern sports stadia and large theatres.
Modern examples.
Smock Alley Theatre in Temple Bar Dublin has two "vomitoria", one stage left and one stage right. The Oregon Shakespeare Festival, for instance, has "vomitoria" in two of its theatres, the outdoor Elizabethan Stage and the Angus Bowmer Theatre. The "voms", as they are called, allow actors to mount the stage from halls cut into the amphitheatre. The Guthrie Theatre in Minneapolis, Minnesota, has two permanent "vomitoria", one at stage left and one at stage right, of its thrust stage. The Circle in the Square Theatre, designed to reflect the theatres of ancient Greece and Rome, is the only Broadway theatre that has a "vomitorium", which is still used in many of their productions as an entrance and exit for the actors.
The Cockpit Theatre, built in London in the 1960s, is one of the very few purpose-built theatres in the round in London, and features four "vomitoria" as corner entrances between four banks of raked seating arranged in a square.
The Chichester Festival Theatre, founded in 1962, was the first of its kind to be opened in the UK for 500 years, because there is no proscenium arch or wings. Instead the stage is a thrust with "vomitoria" or "voms" for the audience and performers to enter and exit.
In addition, the Mark Taper Forum, one of the three theatres making up the Los Angeles Music Center, has two "vomitoria". It has a strong thrust stage such that the audience sit in an amphitheatre-type array.
Winnipeg's second largest theatre, Prairie Theatre Exchange, has two "vomitoria" on either side of their thrust stage, with seating on three sides.
The Denver Center for the Performing Arts' Space Theatre is a theatre "in the round" with a pentagon configuration. It contains five "vomitoria" spaced 72 degrees apart, creating five equal seating sections.
Historical notes.
A commonly held but erroneous notion is that Ancient Romans designated spaces called vomitoria for the purpose of literal vomiting, as part of a binge and purge cycle.