SEO, AEO and GEO glossary: 32 terms in plain English
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Short answer: SEO gets your pages into search results. AEO and GEO get your business into the answers that Google and AI assistants write. The words below are the ones our reports and guides use. Each gets a sentence or three, with a link to the source wherever we state a fact.
AEO (answer engine optimisation)
Writing and structuring pages so they become the answer to a question, not just a link in a list. It grew out of featured snippets and voice assistants, before AI chat existed. Today people use it almost interchangeably with GEO.
More: AEO vs GEO vs SEO
AI crawler
A program that fetches web pages for an AI company. Some collect pages to train models, such as OpenAI's GPTBot and Anthropic's ClaudeBot. Others fetch pages to answer searches, such as OAI-SearchBot and PerplexityBot. You allow or block each one by name in robots.txt.
AI Overviews
Google's AI-written summaries, shown above the normal results for some searches, with links to the pages they draw on. Google says there is nothing extra to add to a page to appear in them. The normal rules for Google Search apply.
AI visibility
How often AI assistants mention your business when people ask about your field without naming you. There is no rank to track, so the only way to measure it is to ask the assistants.
Alt text
A short written description of an image, stored in the page's code. Screen readers read it aloud to people who cannot see the image. Search engines use it to understand what the image shows.
Canonical tag
A line in a page's code that names the main address of that page, for when the same content can be reached at several addresses. Google treats it as a strong signal, not a command.
Citation
A link or source name that an AI answer shows next to a claim, so the reader can check it. Being cited is the AI version of ranking: your page was used, and named.
Core Web Vitals
Google's three measures of how a page feels to use. Largest Contentful Paint (how fast the main content appears) should be 2.5 seconds or less. Interaction to Next Paint (how fast the page reacts to a tap or click) should be 200 milliseconds or less. Cumulative Layout Shift (how much the page jumps around) should be 0.1 or less. Interaction to Next Paint replaced First Input Delay on 12 March 2024.
Sources: web.dev: Web Vitals, web.dev: INP becomes a Core Web Vital
Crawling
A search engine or AI program fetching your pages, by following links and reading your sitemap. A page that is never crawled cannot be indexed, ranked or quoted.
E-E-A-T
Experience, expertise, authoritativeness and trustworthiness. Google uses the term to describe the content it wants to reward, and says trust matters most. Google also says E-E-A-T is not itself a ranking factor. The first E, experience, was added in December 2022.
Sources: Google: creating helpful, reliable, people-first content, Google: E-A-T gets an extra E for Experience (December 2022)
Entity
A distinct thing that a search engine or AI model can recognise: a business, a person, a place, a product. Using the same name, address and description everywhere online helps them connect every mention to the same business.
FAQ rich results
The expandable questions Google used to show under some search results, driven by FAQ structured data. Google limited them to well-known, authoritative government and health sites in August 2023, and stopped showing them altogether on 7 May 2026. FAQ markup does no harm, but it no longer changes how a page appears in Google.
Source: Google: FAQ structured data
Featured snippet
A short extract from one page that Google shows in a box above the normal results, as a direct answer to the search.
GEO (generative engine optimisation)
Making your content more likely to be used and cited in answers written by AI assistants such as ChatGPT, Gemini, Claude and Perplexity. The term comes from a research paper first published in November 2023 and presented at the KDD conference in 2024. Most of the work is the same as good SEO.
More: The GEO checklistSource: GEO: Generative Engine Optimization (arXiv)
Google-Extended
A name you can use in robots.txt to stop Google using your pages to train its Gemini models and to ground Gemini's answers. It is a control, not a separate crawler. Google says it does not affect whether your site appears in Google Search.
More: AI crawlers and robots.txtSource: Google: common crawlers
Grounding
When an AI assistant looks up current web pages before it answers, and bases its answer on them. Grounded answers can cite their sources. Answers that are not grounded come only from what the model learnt in training, which may be out of date.
Hallucination
An AI answer that states something false as if it were fact. Clear facts on your own pages give an assistant something accurate to repeat instead.
Indexing
A search engine storing a page it has crawled, so the page can appear in results. Crawled does not mean indexed: a search engine can fetch a page and still leave it out.
JavaScript rendering
Running a page's JavaScript to build what the visitor sees. Google's crawler does this. A December 2024 study by Vercel and MERJ found that none of the major AI crawlers it measured, including OpenAI's, Anthropic's and Perplexity's, ran JavaScript. Text that only appears after JavaScript runs may be invisible to them.
JSON-LD
The format Google recommends for structured data. It sits in a script block in the page's code, separate from the visible text, so adding it never changes how the page looks.
LLM (large language model)
The kind of AI model behind ChatGPT, Claude and Gemini. It learns from very large amounts of text, and writes answers by predicting the words that should come next.
llms.txt
A proposed text file, at /llms.txt, that summarises a site for AI systems in plain Markdown. Jeremy Howard proposed it in September 2024. No major AI company has said it reads the file, and Google says you do not need one to appear in its AI features.
More: What is llms.txt?Source: Google: AI features and your website
Long-tail query
A longer, more specific search, often a whole question. Each one is searched less often, but the person's need is clearer. It is also how people tend to talk to AI assistants.
Meta description
A one or two sentence summary of a page, stored in its code. Search engines often show it under the title in results. It does not move rankings, but a good one earns more clicks.
robots.txt
A text file at the root of a site that tells crawlers which pages they may fetch. It became an internet standard, RFC 9309, in September 2022. It is a request, not a lock: the standard itself says the rules are not a form of access authorisation.
More: AI crawlers and robots.txtSource: RFC 9309: Robots Exclusion Protocol
Search Console
Google's free tool that shows which searches your pages appear for, how often people click, and any problems Google found while crawling them. Bing has its own version, Bing Webmaster Tools.
SEO (search engine optimisation)
Making pages easy for search engines to find, understand and trust, so they appear for the searches people make. AEO and GEO build on it rather than replace it.
More: AEO vs GEO vs SEO
Snippet controls
Instructions in a page's code that limit how much of the page a search engine may show: nosnippet, data-nosnippet and max-snippet. Google says the same controls limit what appears in its AI features. Set by mistake, they can keep a page's text out of AI answers.
Structured data (schema)
Labels in a page's code that state facts outright: this is an article, this is its author, this is the business address. Most sites use the shared Schema.org vocabulary. It helps machines read a page, but Google says no special structured data is needed to appear in its AI features.
Title tag
The page title stored in its code. It is usually the clickable headline in search results and the name on the browser tab. Google shortens long titles to fit, so put the important words first.
XML sitemap
A file that lists the pages you want search engines to find, with the date each one last changed. It helps crawlers find pages, but it does not guarantee they are indexed.
Zero-click search
A search that ends on the results page, because the answer is shown there and nobody clicks through. In the first year of AI Overviews, to May 2025, BrightEdge measured Google search impressions up 49% and click-through rates down about 30%.
Source: BrightEdge, May 2025
Put the words to work
Most of these terms are things our free checkup tests for you. Run it on your site, or work through the GEO checklist, which says which of our checks covers each step.