Guide · Glossary
AI search glossary: GEO, AEO and the terms that matter
This AI search glossary defines the terms marketers meet when they work on visibility in ChatGPT, Google AI Overviews, Gemini and other AI engines: from generative engine optimization and query fan-out to citations, share of voice and the crawlers that decide whether an engine can read your site.
Updated · By the Cited team
AEO (answer engine optimization)
The practice of getting a brand named and cited in answers from AI engines and answer boxes. In practice the same discipline as GEO. See what AEO is.
AI Mode
Google’s conversational search mode, which answers a question in full with links to supporting pages and lets the searcher ask follow-ups. Google says it may run several related searches (a query fan-out) to build the answer.
AI Overviews
The AI-written summary Google shows above some search results, with links to the pages it drew on. To appear as a link, Google says a page must be indexed and eligible to show with a snippet. See how to rank in AI Overviews.
AI SEO
A common name for optimising content and sites for AI engines as well as search engines. See our AI SEO and GEO guide.
AI visibility
How often, how prominently and how favourably AI engines mention a brand when people ask the questions it wants to win. See how to measure AI visibility.
Average position
Where your brand usually appears in an answer’s list of brands. Lower is better.
Citation
A link from an AI answer to a page it drew on, usually placed next to the claim the page supports. Citations show which pages an engine relied on, and whether your own site is one of them.
Citation rate
How often AI answers quote a given page or website as a source.
Control prompt
A tracked prompt deliberately left without new content, so it shows what happens to answers without our work. Comparing target prompts with control prompts separates the effect of the work from changes in the market.
E-E-A-T
Experience, expertise, authoritativeness and trustworthiness: the qualities Google’s search quality guidelines ask raters to look for in content. Pages that show them clearly, with named sources and real evidence, are easier for search and AI engines to trust.
GEO (generative engine optimization)
The practice of getting a brand mentioned, recommended and cited inside answers written by AI engines. See what GEO is and GEO vs SEO.
GPTBot
OpenAI’s crawler for content that may be used to train its models. Blocking it does not remove a site from ChatGPT search, which uses a separate crawler, OAI-SearchBot.
Grounding
When an AI engine bases its answer on documents it has just retrieved, such as search results, rather than only on what the model learned in training. Grounded answers are the ones new content can change quickly.
LLM
A large language model: the kind of AI model behind ChatGPT, Gemini, Claude and Copilot.
LLMO (LLM optimization)
Another name for GEO: optimising for answers written by large language models.
llms.txt
A proposed Markdown file at a site’s root that summarises the site for language models. Google says no special AI files are needed to appear in its AI features. See does llms.txt help.
Mentions
How many times AI answers name your brand in total.
OAI-SearchBot
OpenAI’s crawler for ChatGPT search. OpenAI says sites that block it will not be shown in ChatGPT search answers, so it should be allowed in robots.txt.
Prompt
A question tracked across AI engines, worded the way buyers ask it, such as “best payroll software for startups”. A prompt set is the list of prompts a brand tracks.
Query fan-out
The extra searches an AI engine runs while composing an answer. A question about “the best boxing gym in Williamsburg” may fan out into searches for reviews, prices and beginner classes. Google says AI Overviews and AI Mode may use it, and ChatGPT shows its searches too.
Sentiment
How favorably AI answers describe your brand, on a scale from 0 to 100.
Share of voice
Your share of AI mentions against the competitors you track.
Source
Any page an AI engine lists as having used for its answer. A citation is the narrower case: a link placed in the answer itself.
Visibility
How often AI answers mention your brand when people ask the questions you care about.
Zero-click search
A search answered on the results page or in an AI answer, so the searcher never clicks a link. As more searches end this way, being named in the answer matters as much as ranking below it.
Questions
What is the difference between a source and a citation?
A source is any page an AI engine lists as used for its answer. A citation is a link placed in the answer itself, usually next to the claim the page supports. Citations show what the engine relied on for a specific claim.
Are GEO, AEO and LLMO different things?
No. They are three names for the same work: earning mentions and citations in AI-written answers. GEO and AEO are the most searched.
Which AI crawlers should a site allow?
At least the search crawlers: Googlebot, Bingbot, OAI-SearchBot for ChatGPT search, and the crawlers of Perplexity and Claude. Training crawlers such as GPTBot are a separate choice and don’t affect search answers.