A medium is a form that a genre is delivered in. Before the digital age, a medium was a tangible thing, a book or a film. In the digital age the term is more akin to a category. A Science Fiction novel is delivered in the medium of a book, but that book might be adapted as a film (one medium) or as a television show (another medium) or even a game (yet another medium). This situation can be very confusing since a medium such as television can contain many different types of (for example) Science Fiction, while one work of Science Fiction may span many different mediums. We find that Star Trek exists as various television shows, movies, books and games. In this case, Star Trek would be a genre (more appropriately a sub-genre) which is delivered in many different mediums.