AI buzzword dictionary

What is Hallucination?

When an AI confidently produces information that is false or made up.

What this actually means

Because a language model generates likely-sounding text, it can invent facts, quotes, statistics or references that look genuine.

It is not lying on purpose; it has no built-in sense of truth. That is why checking matters.

Example

Asked for sources, an assistant lists a journal article with a real-sounding title and authors — but the article does not exist.

Where you may meet it

Anywhere AI gives facts: research summaries, legal or medical questions, citations, product specifications.

Related terms and lessons

RAG (retrieval-augmented generation)A method where an AI first looks up relevant documents, then uses them to write its answer.Large language model (LLM)A type of AI trained on huge amounts of text to predict and generate language.PromptThe instruction or question you give an AI tool.How to check whether an AI answer is rightAI assistants can be wrong while sounding certain. Checking takes a few minutes and protects you from passing on mistakes.Using AI for reports and researchAI is useful for structure, summaries and first drafts. It is weakest at facts and sources, so research still needs checking.

Last reviewed: 25 September 2026