hallucination

Definition of hallucination

1. : a confident but false or made-up statement produced by an AI model, such as an invented fact, quote, citation, or source

   • The brief cited six court cases that turned out to be hallucinations.
   • Grounding the model in real documents cuts hallucinations sharply.

2. : (hallucinate, verb) to produce such a false output

   • It hallucinated a book that the author never wrote.