1

Alternate Universe (also known as alternate reality), is commonly abbreviated as AU and it is a descriptor used to characterize fanworks which change one or more elements of the source work's canon. The term most often refers to fanfiction, but fanart can also depicted the characters in AUs.

Unlike regular fanfiction, which generally remains within the boundaries of the canon set out by the author, alternate universe fiction writers like to explore the possibilities of pivotal changes made to characters' history, motivations, or environment.