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. The document discusses how genre helps audiences choose what type of art to consume and filmmakers determine the key aspects to include when creating a work for a particular genre, such as thrillers. It then analyzes the opening scenes of two thriller films, Shutter Island and The Silence of the Lambs, noting the use of fog, music, and isolated settings to build tension and unease for the audience.