AU

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.