Genre refers to the different styles or categories of art such as films, literature, music, and photography. The genre provides expectations for the audience about the theme or subject matter of the piece. For example, people expect a horror film to scare them. Genres help audiences choose what type of art to consume based on the genre. The document discusses how genres create expectations and discusses the thriller genre specifically, analyzing the opening scenes of films like Shutter Island and The Silence of the Lambs.