Glossary · Updated Sep 2, 2026

Hallucination

When an AI model states something false or invented with confidence, such as a fake citation or a wrong fact.

Definition

Hallucinations occur because language models generate plausible continuations rather than verified truths. They are more common on obscure topics, precise numbers, citations, and questions outside the model's training data. Mitigations include grounding answers in retrieved documents, requiring citations, lowering creativity settings, and human review for high-stakes output.

Why it matters when choosing a tool

Every AI tool can hallucinate; the difference is how visibly it shows sources and how easily you can verify claims before relying on them.

Where you will meet it

AI Research & Search, AI Legal & Contracts, AI Customer Support

Related terms

Grounding · Citations in AI answers · Retrieval-augmented generation (RAG) · Guardrails

Tools where this matters

Reviewed products in the related categories