Plain-English AI definitions for legal professionals. For what bars actually require, see the Legal AI Compliance Register.

Large language model (LLM)

Core concepts Last reviewed 2026-06-11

Definition A neural network trained on massive text corpora to predict the next token, producing fluent text. The engine behind ChatGPT, Claude, and Gemini.

In more depth

Large language models learn statistical relationships between words by processing enormous volumes of text during training. At run time they generate answers one token at a time, choosing each next piece by probability rather than looking facts up in a database, which is why they can draft and summarize well yet still state falsehoods confidently. Lawyers using LLMs remain responsible for verifying output and for keeping client information out of tools whose data terms have not been reviewed.

Further reading: Wikipedia.

Related terms

About the editor: MHSB Solutions, Research desk. MHSB Solutions is not a law firm. This glossary is educational information, not legal advice.

Educational information, not legal advice. AI terminology and tools change quickly; definitions reflect usage as of the last-updated date. For what bar associations and courts actually require of lawyers using AI, see legalaicompliance.help and consult a licensed attorney in your jurisdiction.