1. In the theatre, an area behind the stage or performance space that is not visible to the audience.
2. (back region) Goffman's metaphor for a private place where a person does not have to keep up appearances. He likens a person's public persona to a performance. Front stage (or front region) areas are places where a person is performing under the scrutiny of others and backstage areas are private spaces where a person can either relax or rehearse future performance strategies: for example, in a restaurant the kitchen is the backstage area where the staff can drop the veneer of politeness. See also dramaturgy; public and private spheres.
http://www.unlv.edu/centers/cdclv/ega/index.html Erving Goffman archives