A spin-off is when a story or characters from a show, movie, or book are used to create a new show, movie, or book. For example, let's say a character from a movie called "Jungle Adventure" gets so popular that people want to learn more about him. The filmmakers could decide to make a new movie, just about this character, to give the fans more information. This new movie would be called a spin-off because it is based on the original movie "Jungle Adventure".