Quick definition · 2 min AI term
Hallucination
A hallucination is when an AI states something false with total confidence, inventing facts, sources, or quotes.
Think of it like
A student who never says “I do not know.” When unsure, they make up a convincing answer instead.
Example
Ask for a citation and a model might invent a real-sounding paper that does not exist. That is a hallucination.
Why it matters
It is the question beginners ask most. Knowing AI can confidently make things up is the single most important safety lesson.
Where you’ll see it
every chatbotChatGPTClaude