Alternate history or
alternative history, sometimes abbreviated as
AH, is a
genre of fiction consisting of stories in which one or more historical events occur differently from
reality. These stories usually contain "what if" scenarios at crucial points in history and present an outcome of events alternative to historical record. The stories are the product of conjecture, but are sometimes based on scientific fact. Alternate history can be seen as a sub-genre of
literary fiction,
science fiction, and/or
historical fiction; different alternate history works may use tropes from any or all of these genres. Another term occasionally used for the genre is "allohistory" (literally "other history").