A film genre is a stylistic or thematic category for motion pictures based on similarities either in the narrative elements, aesthetic approach, or the emotional response to the film. Drawing heavily from the theories of literary-genre criticism, film genres are usually delineated by "conventions, iconography, settings, narratives, characters and actors." One can also classify films by the tone, theme/topic, mood, format, target audience, or budget. These characteristics are most evident in genre films, which are "commercial feature films [that], through repetition and variation, tell familiar stories with familiar characters and familiar situations" in a given genre.