Glossary

The AI search glossary

Plain-English definitions of the AI search and GEO terms that matter in 2026 — generative engine optimization, answer engine optimization, Google AI Overviews and llms.txt — each linking to a full guide.

Generative Engine Optimization (GEO)
Generative Engine Optimization (GEO) is the practice of optimizing content so that AI answer engines — ChatGPT, Google AI Overviews, Perplexity and Gemini — cite it when generating answers.
Answer Engine Optimization (AEO)
Answer Engine Optimization (AEO) is the practice of structuring content to win direct answers — featured snippets, voice results and AI answers — by answering specific questions concisely and clearly.
Google AI Overviews
Google AI Overviews are AI-generated summaries shown at the top of Google’s search results that answer a query directly and link to a small set of cited source pages.
llms.txt
llms.txt is a proposed plain-text standard file, placed at a site’s root, that gives AI engines a curated, machine-readable index of a site’s most important content.

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