GEO glossary: the vocabulary of AI visibility
Every term explained in plain words, with an example.
45 terms shown
GEO basics
The basic words for understanding what visibility in AI means, and how it differs from SEO.
- GEOGEO covers the practices that make a brand visible in the answers of generative AI such as ChatGPT, Gemini, Claude or Perplexity.
- AEOAEO means optimizing content for engines that give a direct answer: featured snippets, voice assistants and generative AI.
- LLMOLLMO is the optimization of a brand and its content for large language models, the ones that power ChatGPT, Claude or Gemini.
- AI SEOAI SEO is the everyday name for the work that makes a brand visible in the answers of AI assistants.
- AI visibilityAI visibility measures how often, in what position and in what way a brand appears in the answers of generative AI.
- SEOSEO optimizes a site for traditional search engines. It is still the foundation of GEO, but it's no longer enough to get recommended by AI.
- Generative engineA generative engine writes an answer from several sources instead of showing links. Examples: ChatGPT Search, Perplexity.
- Conversational searchConversational search replaces keywords with full questions, put to an AI in natural language, with follow-ups.
- Zero-click searchA zero-click search ends without the user clicking a link, because the answer appears directly: a snippet, an AI Overview or an AI answer.
AI search engines
The assistants and generative engines where a brand can be cited, and what sets them apart.
- ChatGPT SearchChatGPT Search is ChatGPT's web search feature: it reads pages when it answers and cites its sources.
- PerplexityPerplexity is an AI answer engine that searches the web for every question and always cites its sources.
- Google AI OverviewsAI Overviews are the AI-generated summaries Google shows at the top of its search results, with links to their sources.
- Google AI ModeAI Mode is Google's conversational search mode: an answer written by Gemini, with follow-ups, instead of the results page.
- GeminiGemini is Google's family of AI models, and the conversational assistant of the same name, which replaced Bard in 2024.
- ClaudeClaude is Anthropic's AI assistant. It answers from memory or by searching the web, and Anthropic sends its own crawlers to read sites.
- Microsoft CopilotCopilot is Microsoft's AI assistant, built into Windows, Edge, Bing and Microsoft 365. It looks up its information in Bing's index.
- Le ChatLe Chat is the AI assistant of Mistral AI, a French company. It can search the web and cite its sources.
How AI builds its answers
What happens between the question asked and the answer shown.
- LLMAn LLM is an AI model trained on huge volumes of text to understand and produce language. It is the engine behind ChatGPT, Claude or Gemini.
- RAGRAG lets an AI look for documents before answering, then write its answer from what it found.
- GroundingGrounding means basing an AI's answer on verifiable sources rather than on its memory alone.
- Query fan-outQuery fan-out is the technique a generative engine uses to split a question into several searches run in parallel.
- HallucinationA hallucination is false information presented confidently by an AI: an invented price, a feature that doesn't exist, a fake quote.
- Knowledge cutoffThe knowledge cutoff marks the end of a model's training data. Whatever happened after it escapes the model, unless it searches the web.
- PromptA prompt is the question or instruction you give an AI. In AI visibility, prompts are the questions your customers actually ask assistants.
- EntityAn entity is something that can be identified without ambiguity: a brand, a person, a place. Search engines link entities together in knowledge graphs.
Measuring AI visibility
The metrics that tell you whether a brand is cited, in what position and against whom.
- Brand mentionA mention is when an AI names your brand in its answer, with or without a link to your site.
- CitationA citation is when an AI points to a page as a source of its answer, with a link. Unlike a plain mention, it can bring traffic.
- AI share of voiceAI share of voice measures your brand's place in AI answers compared with your competitors'.
- Answer positionPosition tells you at what rank a brand appears in an AI answer. Being named first isn't worth the same as being named last.
- SentimentSentiment describes the way an AI talks about your brand: positively, neutrally or negatively, and with what arguments.
- Prompt trackingPrompt tracking means asking AI the same questions at regular intervals to follow how a brand's visibility changes.
- AI visibility scoreAn AI visibility score sums up in one number, often out of 100, a brand's presence in AI answers on a panel of questions.
- AI trafficAI traffic covers the visits a site gets from AI assistants and generative engines, when a user clicks on a cited source.
- Reference sourcesReference sources are the few sites AI cites by default in a category: review sites, comparisons, encyclopedias, specialist media.
Optimizing for AI
The technical and editorial levers that make a brand readable and citable by AI.
- llms.txtllms.txt is a file placed at the root of a site that introduces the brand to AI and lists the pages to read first.
- robots.txtrobots.txt is the file that tells crawlers, including AI crawlers, which parts of a site they're allowed to visit.
- AI crawlerAn AI crawler is a bot that browses the web on behalf of an AI company, to train its models or feed its answers.
- GPTBotGPTBot is the OpenAI crawler that collects pages to train its models. OpenAI uses other crawlers for ChatGPT's search.
- Google-ExtendedGoogle-Extended is a robots.txt token that lets you refuse the use of your pages for Gemini models. It has no effect on Google Search.
- Structured dataStructured data describes a page's content in a machine-readable format, using the Schema.org vocabulary, often in JSON-LD.
- E-E-A-TE-E-A-T stands for the four qualities Google looks for in content: experience, expertise, authoritativeness and trustworthiness.
- JavaScript renderingWhen a page's content only appears after JavaScript runs, most AI crawlers don't see it. Server-side rendering fixes the problem.
- Citable contentCitable content is written so AI can reuse it as is: one idea per paragraph, precise facts, a direct answer to a question.
- UGCUGC covers content published by users: reviews, forums, Reddit, videos. AI relies on it heavily to size up a brand.
- Digital PRDigital PR gets a brand talked about in media and on third-party sites. In GEO, it's often what gets a brand into AI answers.
Three questions to start with
What is GEO?
GEO, short for Generative Engine Optimization, covers the practices that make a brand visible in the answers of generative AI: ChatGPT, Gemini, Claude, Perplexity or Google's AI Overviews. Where SEO aims for a spot in a list of links, GEO aims for a spot in the answer itself. It is measured in mentions, citations and position in those answers.
Read the full definitionWhat is the difference between SEO and GEO?
SEO works on your position in Google's results. GEO works on your presence in the answers written by AI, which often name only two to five brands. The two go together: many generative engines look for their sources in a search index, so good SEO helps your GEO, without guaranteeing it.
Read the full definitionGEO, AEO, LLMO: are they the same thing?
Almost. All three refer to optimizing for AI answers. AEO comes from featured snippets and voice assistants, LLMO focuses on what models know about your brand, GEO on the generative engines that search the web when they answer. You will also hear it called AI SEO.
Read the full definitionWhere the numbers come from
Every number in the glossary names its source in the sentence. This vocabulary moves fast: we reread the definitions when an engine changes the way it answers.
- Semrush AI Visibility Index 2026, 126 million prompts, ChatGPT, Gemini, AI Mode and AI Overviews
- Promptwatch, August 2026, the drop in Reddit citations in ChatGPT
- Pew Research Center, 2025, clicks on Google when an AI summary is shown
- Vercel and MERJ, JavaScript rendering by AI crawlers
- GEO: Generative Engine Optimization, 2023, the Princeton and Georgia Tech paper that named GEO
- OpenAI, Anthropic and Google documentation, the crawlers and what each one does
You know the vocabulary. Now see what AI says about your brand.
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