AU (Alternate Universe): refers to a story of which there is a (often major) plot, setting, or character deviation away from established canon. AUs may be anything, but there are some themes that are quite common in a variety of fandoms such as Historical AUs, Animal AUs, Highschool AUs, and/or Modern AUs, for example. Authors may also create and develop their own unique worlds in which to place familiar characters. Sometimes referred to as Alternate Realities, Alternate Timelines or Parallel Realities, but such precise distinctions are not usually necessary.
See also: Fusion and/or Worldbuilding
JE LEEST
A-Z Fanfiction Guide: Terms to Know
OverigAn A-Z List of all the fanfic terms YOU should know! (Cr. Goes to Angerfire.com for references and information) * this will be updated periodically, so if some things are missing, they haven't been added yet.