Home Glossary
AI search terms, in plain English.
Short definitions of the words used about AI search and generative engine optimisation. Platform terms follow the platforms' own documentation, checked on 12 October 2026.
- AI Mode
A Google Search mode, shown as a tab on the results page, that answers longer, multi-part questions in conversation and supports follow-ups. Google launched it in the UK on 28 July 2025. A page must be indexed and eligible for a snippet to appear in it.
- AI Overviews
AI-written summaries that appear at the top of some Google Search results, with links to the pages they draw on. Google shows them only when its systems judge them useful for the query.
- AI search visibility
How often, and how accurately, AI search tools name a business when people ask questions it could answer. We measure it as a count across many saved answers, such as named in 9 of 40 answers.
- Answer engine optimisation (AEO)
Another name for work that aims to get a business or page used in AI-written answers. In practice it overlaps almost entirely with generative engine optimisation.
- Appearance rate
The share of answers that name a business, out of all answers recorded for a fixed question set. For example, a business named in 9 of 40 recorded answers has an appearance rate of 9 in 40.
- ChatGPT search
ChatGPT's web search feature. It searches the web when a question would benefit from current information, shows citations to the pages it used, and is available to people who aren't signed in. OpenAI says it sometimes works with third-party search providers.
- Citation
A link or reference in an AI answer to a source it relied on, such as a business website, a Google Business Profile or a directory page. Being cited and being named are different things: an answer can name a business without citing its website.
- Crawler
Software that visits web pages automatically so a search engine or AI service can read them. Examples include Googlebot, Bingbot and OAI-SearchBot. Websites control crawler access with robots.txt.
- Entity
A specific, identifiable thing, such as a business, person or place, that search engines and AI tools keep facts about. Consistent names, addresses and identifiers across the web make it easier for them to recognise that several sources describe the same business.
- Generative engine optimisation (GEO)
The work of making a business, product or page more likely to be found, cited and described accurately in answers written by AI tools. The term comes from a 2023 research paper by Aggarwal and colleagues; Bing now describes GEO as the practice of understanding how content participates in AI-driven experiences.
- Google Business Profile
The free listing that shows a business's name, address, hours, photos and reviews in Google Search and Maps.
- Google-Extended
A robots.txt product token that lets publishers manage whether content Google crawls is used for training and grounding in some of Google's AI systems outside Search. Google says it doesn't affect inclusion or ranking in Google Search.
- GPTBot
OpenAI's crawler for content that may be used to train its AI models. It's separate from OAI-SearchBot, so a site can block training while staying open to ChatGPT search.
- Grounding
Connecting an AI model's answer to current information retrieved from the web or another source, so the answer can be based on, and cite, real pages. Bing describes grounding as the system that connects AI to current, authoritative information.
- Hallucination
An AI answer that states something false as fact. For businesses, the usual examples are wrong prices, wrong opening hours or a service the business doesn't offer. Most errors we log trace back to a source that's unclear, out of date or contradicted elsewhere.
- IndexNow
A protocol that lets a website tell participating search engines, including Bing, as soon as a page is added, changed or removed. Submitting a URL doesn't guarantee it will be indexed.
- Large language model (LLM)
The kind of AI model behind tools such as ChatGPT, Gemini and Copilot. It writes text by predicting likely words, which is why it can state errors fluently and why its answers vary between runs.
- llms.txt
A proposal, published by Jeremy Howard in September 2024, for a Markdown file at a website's root that summarises the site for AI tools. It remains a proposal. Google says you don't need AI text files to appear in its AI features.
- Microsoft Copilot
Microsoft's AI assistant. Bing Webmaster Tools' AI Performance report, in public preview since February 2026, shows how often a site is cited in Copilot and in AI-generated summaries in Bing.
- NAP consistency
Keeping a business's name, address and phone number identical everywhere it appears: website, Google Business Profile, directories and social profiles. Inconsistent details are a common cause of wrong AI answers.
- OAI-SearchBot
OpenAI's crawler for ChatGPT search. OpenAI says sites that block it won't be shown in ChatGPT search answers, though they can still appear as navigational links. Changes to robots.txt take about 24 hours to apply.
- Query fan-out
A technique Google says AI Overviews and AI Mode may use: issuing multiple related searches across subtopics and data sources to build one response.
- Review gating
Asking only customers likely to leave a positive review, or filtering out unhappy ones before they reach a review site. Google's policy prohibits selectively soliciting positive reviews.
- robots.txt
A text file at the root of a website that tells crawlers which parts of the site they may visit. Blocking a search or AI crawler here can keep a site out of that platform's answers.
- Structured data
Code added to a web page, usually in schema.org vocabulary and JSON-LD format, that states facts such as a business's name, address and opening hours in a machine-readable way. Google recommends it matches the visible page, and says no special structured data is needed for its AI features.
Sources for platform definitions are listed in our guides. Missing a term? Email hello@inplaincite.com.