X-rated films are movies that contain explicit sexual content and are intended for adult audiences only. These films are typically rated by organizations like the Motion Picture Association (MPA) in the United States, which assigns ratings to help viewers understand the nature of the content. The X rating indicates that the film is not suitable for viewers under 17 or 18, depending on the region. Historically, the X rating was used to categorize adult films, but it has since been replaced by the NC-17 rating in the U.S. to provide a clearer distinction. X-rated films can include a variety of genres, but they primarily focus on sexual themes and graphic depictions.