Genre refers to any category of art or entertainment based on stylistic criteria, such as literature, music, or films. There are four main genres - literary, film/television, video games, and music - which are further divided into subgenres like action, adventure, comedy, and horror. Horror films aim to elicit negative emotions in viewers by playing on primal fears using themes of the macabre and supernatural, often involving the intrusion of an evil force into the everyday world through devices like ghosts, monsters, and serial killers. Common conventions in horror films include isolated settings, interrupted communication, early killings, storms, and the use of lighting, camera angles, and sounds to build tension.