A fictional fact.
Ficts are the basic building blocks of fictional worlds, events, people, etc. Ficts are not lies, nor are they false. They are best understood as true facts about fictional realities. For example:
Falsehood: The Kiwi is a carnivorous, fire-breathing animal, with an average length of 19 meters, and which feeds almost exclusively on humans. This is false in the "real world" (fortunately).
Fict: Pfwillic is a country which stretches along the eastern coast of the continent Ias of the planet Drowlto VI. This is true in one of the many fictional universes described on Fictopedia, but false in the "real world".
Fictopedia is an online encyclopedia of user-created ficts, which is really, really fun to read and edit. This is true in every possible universe.