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

Token

How models work Last reviewed 2026-06-11

Definition The small unit of text a language model actually reads and writes—a word, part of a word, or punctuation mark. Models measure input size, output length, pricing, and usage limits in tokens.

In more depth

Before processing, text is split into tokens using a fixed vocabulary; common words may be a single token while rare or technical terms are broken into several. The model then predicts its output one token at a time. Token counts matter practically because they determine how much material fits in a model's context window and how API usage is billed—long documents such as contracts or deposition transcripts consume many thousands of tokens.

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.