A prequel is a literary, dramatic, or cinematic work whose story precedes that of a previous work, by focusing on events that occur before the original narrative. It is a work that forms part of a backstory to the preceding work. The term "prequel" is a 20th-century neologism from the prefix "pre-" (from Latin prae, "before") and "sequel". Prequels may or may not concern the same plot as the work from which they are derived. More often, they explain the background that led to the events in the original, but sometimes the connections are not completely explicit. Sometimes prequels play on the audiences knowledge of what will happen next, using deliberate references to create dramatic irony.

A sequel, on the other hand, is a literary, dramatic, or cinematic work that follows the story of a previous work, by focusing on events that occur after the original narrative. It is a continuation of the story, often featuring the same characters and settings as the original work. Sequels may or may not concern the same plot as the work from which they are derived. They can pick up where the original story left off or take place years later.

In summary, a prequel is a work that takes place before the original story, while a sequel is a work that takes place after the original story.