Summary: Plain-language definitions of the AI terms that come up in product and design work, from tokens and context windows to agents, evals, and prompt injection.

AI conversations run on a lot of specialized language. Use this glossary to look up a term you have run into, or to build a working vocabulary before you need one. Definitions follow how the terms are used in AI products and UX work; vendors and researchers sometimes use them differently. Many entries link to NN/G articles that go deeper; for a guided tour of the topic, start with our study guide on how AI works and how users think about it .

Look up the term you need in the table below, search this page with your browser’s Find command, or read straight through.…