Visibility Mesh · Glossary

The vocabulary of AI visibility.

These are the terms behind AI search, defined plainly. Start anywhere.

Each entry defines one term you will meet when you work on how AI systems read and cite your website. Definitions are short on purpose, so anyone can quote one on its own.

Several of these terms are vendor labels for the same work, and the entries say so. When a term describes what happens inside an AI system, the definition cites the company that runs it. Visibility Mesh measures the website side. We cannot see inside ChatGPT or Google any better than you can.

01
AI visibility
AI visibility is how often and how accurately AI assistants and AI search features find a business, describe it and name or cite it when people ask questions the business can answer. The guide to what AI visibility means covers the work and how to measure it.
02
Answer engine
An answer engine is a system that answers a question directly instead of returning a list of links.
03
Answer Engine Optimization (AEO)
Answer Engine Optimization is the work of making your website easy for the systems that answer people directly to read and quote.
04
Generative engine optimization (GEO)
Generative engine optimization, or GEO, is the work of making a website and its facts easy for AI systems that write answers, such as ChatGPT, Perplexity and Google AI Overviews, to find, read and cite. The page on generative engine optimization explains where the term came from.
05
AI legibility
AI legibility is how completely an AI crawler can read and understand your website.
06
Entity recognition
Entity recognition is how AI identifies your brand as one known, consistent thing it can cite with confidence.
07
The mesh
The mesh is our name for the connected layer of structured data that tells AI who you are and what you offer.
08
Agentic commerce
Agentic commerce is shopping in which AI agents browse, compare and buy on behalf of a person.
09
AI discoverability
AI discoverability is whether AI systems can find and understand a business, its products and its pages at all. A system has to find your pages before it can recommend them. Once a system has found the pages, AI legibility describes how well it can read them.
10
LLMO (large language model optimization)
LLMO is another name vendors use for making content easier for AI models to find, use and cite. It describes the same work as generative engine optimization (GEO), under a different label.
11
AI SEO
AI SEO is a loose label with two meanings. It can mean optimizing a website so AI search systems use and cite it, or it can mean ordinary SEO done with the help of AI tools. Ask a vendor which one it means before you compare prices. The comparison of SEO, AEO and backlinks covers the first meaning.
12
AI citation
An AI citation is a link or a named source that an AI answer shows as the basis for what it says. Google shows supporting links in AI Overviews and AI Mode. Microsoft counts these citations for your pages in the AI Performance report in Bing Webmaster Tools, and our guide to that report shows where to find it.
13
Prompt tracking
Prompt tracking means saving the questions people ask AI assistants and asking them again on a schedule. Each run shows which brands and sources the answers name. Answers vary between runs, so one run is only a sample. The guide to checking what AI says about your brand shows a method that allows for that.
15
Query fan out
Query fan out is Google's name for the related searches that AI Overviews and AI Mode may run to build one answer. Those searches reach across subtopics and data sources. Some sites answer fan out with a separate page for every variation of a question. Google warns that content made mainly to manipulate its rankings or its AI answers breaks its scaled content abuse policy.
16
Grounding (retrieval)
Grounding is the step where an AI system fetches current web pages and uses them to write and support its answer. Google calls the technique retrieval augmented generation, also known as grounding. Microsoft says grounding is the source material and web evidence that an AI system uses to support and cite a response.
17
AI Overview
An AI Overview is an AI generated snapshot that Google Search shows for some searches, with links to pages that support it. Google shows one only when its systems judge that it adds to the classic results. Many searches show none. The guide to appearing in Google AI Overviews covers what a website can do.
18
AI brand monitoring
AI brand monitoring is the ongoing check of what AI assistants say about a brand. It looks at whether they mention the brand, how they describe it and whether the description is accurate. It relies on prompt tracking, since single answers vary.

Want to see which of these apply to your own website? Run a free scan of up to five key pages, and look at what an AI crawler found.

Sources, each read on September 26, 2026: Google Search Central, AI features and your website (last updated December 10, 2025); Google Search Central, optimizing your website for generative AI features on Google Search (last updated July 10, 2026); Google Search Help, AI Overviews in Google Search; Bing Webmaster Blog, AI Performance in Bing Webmaster Tools (February 10, 2026); Bing Search Blog, new AI visibility insights in Bing Webmaster Tools (June 16, 2026); and SparkToro, less than one third of Google searches still send a click (June 9, 2026).