Transmedia Storytelling - A process in which a story is told over many medias using current technology. Examples of media are: movies, video games, comic books, action figures, and amusement parks. An example of transmedia storytelling could be a story that is introduced in a film and expanded through television, novels, and comics (Jenkins 98). The expansion over the different media would be considered transmedia storytelling.
Jenkins discusses why The Matrix is a very good example of how this technique is used. The Matrix was introduced by Hollywood film, yet the entire story could not be known without delving deep into comics, games, and other media.
Other examples we see today are Pokemon, Superman, Batman, .hack//Sign, etc.