Definitions
1.NounThe division between the fictional world depicted, and the actual actors, props, etc.
2.NounThe divide between critics or audience members and author or theater practitioner.
3.NounAny of various other divisions between groups of people in the theatre.
4.NounThe ceiling.
5.NounThe floor.
6.NounUsed other than figuratively or idiomatically: see fifth, wall.