Cabaret is a form of entertainment featuring music, song, dance, recitation or drama. It is mainly distinguished by the performance venue (also called a cabaret), such as in a restaurant, pub or nightclub with a stage for performances. The audience, often dining or drinking, does not typically dance but usually sits at tables.
Musicals101.com Outstanding article in three parts by John Kenrick on the history of cabaret and its evolution as a theatrical genre.
The Guide to Musical Theatre Excellent article on the history of German cabaret.
Wikipedia Worthwhile encyclopedic entry on cabaret, French cabaret and German cabaret.