AU
/eɪ juː/
Very CommonAlternate Universe. A fanfiction setting that changes key facts about the original story or characters.
AUs can range from small changes (same world, different job) to completely unrelated universes where only the character names and personalities carry over. The appeal is seeing how familiar characters would behave in new circumstances.
Real-world examples3 examples
| # | Example | What it means | Source |
|---|---|---|---|
| 01 | someone write me a bakery AU where they keep arguing about the croissants please. | The speaker wants a specific type of alternate universe story for a favorite pairing. | tumblr, 2023 |
| 02 | I don't even watch that show but I have read 40 AUs for it. | The person is a fan of the fanfiction community around a show without actually watching it. | tumblr, 2022 |
| 03 | rivals at a law firm AU with enemies to lovers? I am going to be ill. | A specific AU concept combining multiple beloved tropes has overwhelmed the speaker in a good way. | x, 2024 |
Use it when
- Describing a fanfic that places characters in a different world or setting.
- Tagging a fanfic that noticeably departs from the source material's timeline or world.
- Requesting a specific alternate setting for a favorite pairing.
Do not use it when
- The story stays within the source material's canon world with only small changes.
Origin and context
Acronym for 'Alternate Universe'. Became a standard tagging convention on fanfiction archives and fandom forums in the early 2000s.
- First seen
- early-2000s
- Confidence
- medium
Cite this page
Use this stable URL to reference the entry.
https://slang.fyi/auUpdated: 2026-08-28License: CC BY 4.0