# The GEO glossary in plain English.

> Every AI search term we use on this site, defined in one line, with a page that explains it properly.

Updated September 24, 2026 · AI Syndicate team · https://www.aisyndicate.com/glossary/

**Quick answer:** This glossary defines the words used in **GEO** (Generative Engine Optimization) — the work of getting a business found, trusted and quoted by AI search like ChatGPT, Google AI Overviews, Perplexity, Gemini and Copilot. Each term gets one plain-English line below, and a full page with examples and sources.

## What do the main AI search terms mean?

Terms are listed A to Z. Each link opens the full definition.

| Term | What it means, in one line | Read more |
| --- | --- | --- |
| AEO (Answer Engine Optimization) | Getting your page picked as the answer AI chat and answer boxes give | [AEO guide](/answer-engine-optimization/) |
| agents.md | A Markdown file for AI agents — an open format for coding tools, and a name some websites use for agent notes | [agents.md](/glossary/agents-md/) |
| AI Access score | AI Syndicate's 0–100 score for whether AI engines can find, read and trust a site well enough to cite it | [AI Access](/ai-access/) |
| AI citation | When an AI answer names or links a source for what it says | [AI citation](/glossary/ai-citation/) |
| AI crawlers | The bots AI companies send to read web pages, for training, search or a live user request | [AI crawlers](/glossary/ai-crawlers/) |
| AI hallucination (brand) | A confident but false statement an AI makes about a business | [AI hallucination](/glossary/ai-hallucination-brand/) |
| AI share of voice | How often AI answers name your brand versus competitors, across your buyers' questions | [AI share of voice](/glossary/ai-share-of-voice/) |
| Entity optimization | Making it unmistakable to machines exactly which business you are | [Entity optimization](/glossary/entity-optimization/) |
| GEO (Generative Engine Optimization) | Getting a business found, trusted and quoted by AI search | [GEO guide](/generative-engine-optimization/) |
| GEO vs SEO | SEO wins a spot in the list of links; GEO wins a place inside the AI answer | [GEO vs SEO](/geo-vs-seo/) |
| llms.txt | A short Markdown file at your site's root that summarises the site for AI and links its best pages | [What is llms.txt?](/blog/what-is-llms-txt/) |
| llms-full.txt | One file holding the full text of a site's key pages, for reading in a single fetch | [llms-full.txt](/glossary/llms-full-txt/) |
| RAG (retrieval-augmented generation) | When an AI looks things up first, then writes its answer from what it found | [RAG](/glossary/retrieval-augmented-generation/) |
| SEO (Search Engine Optimization) | Earning higher places in search engines' ranked results | [SEO guide](/search-engine-optimization/) |
| Zero-click search | A search that ends without a click to any website | [Zero-click search](/glossary/zero-click-search/) |

> **A note on what's required.** Google says there are no special files, markup or optimizations needed to appear in AI Overviews or AI Mode — a page must be indexed and eligible for a snippet in Search. [Google Search Central](https://developers.google.com/search/docs/appearance/ai-features) Terms like llms.txt and agents.md are optional extras; crawler access and clear pages come first.

## FAQ

### What is the difference between GEO and AEO?

GEO is the broad work of being found, trusted and quoted by AI search. AEO focuses on being picked as the single answer for a specific question. Our [GEO vs AEO](/geo-vs-aeo/) page compares them.

### Which term should a business owner learn first?

AI crawlers. If AI bots can't read your site, most of the rest of this list can't help.

### How often is this glossary updated?

Each page shows the date it was last changed, and every source lists the date we read it.

## Sources

1. [AI features and your website](https://developers.google.com/search/docs/appearance/ai-features) — Google Search Central. Read Sep 24, 2026.