Resource
AI SEO Glossary.
Plain-English definitions for every AI SEO, Generative Engine Optimization (GEO), Answer Engine Optimization (AEO) and LLM SEO term in 2026. Updated as the field moves.
- AEO (Answer Engine Optimization)
- Optimizing content so it appears as the direct answer in Google AI Overviews, featured snippets and other answer-engine surfaces. Overlaps heavily with GEO and SEO.
- AI Overviews
- Google's AI-generated summary that appears at the top of search results for many queries. Pulls from indexed pages, cites sources, replaces the ten-blue-links experience for the user who reads it.
- AI Mode (Google)
- Google's chat-first search experience launched in 2025. Full conversational interface built on Gemini. Separate surface from AI Overviews.
- Answer Block
- A paragraph or short section that directly and completely answers a specific question. AI assistants lift answer blocks verbatim when citing a page. Pages built around answer blocks get cited; pages built around marketing copy do not.
- ChatGPT
- OpenAI's AI assistant. Largest AI assistant by traffic (around 52% market share as of mid-2026). ChatGPT Search is the real-time web-grounded mode that cites sources.
- Citation
- A reference by an AI assistant to a specific URL or brand inside its response. Equivalent to a search ranking but inside the answer rather than on a results page. The core unit of GEO measurement.
- The percentage of AI responses in a given query set that cite your business versus competitors. The primary GEO performance metric. Replaces or supplements traditional keyword rank.
- Claude
- Anthropic's AI assistant. Around 9% market share as of mid-2026 and growing fastest among the top three. Known for long-form reasoning and careful source handling.
- Copilot (Microsoft)
- Microsoft's AI assistant. Built on OpenAI models, integrated into Bing, Windows and Microsoft 365. Separate citation surface from ChatGPT despite the shared backend.
- Crawl
- The process by which AI assistants and search engines discover and read web pages. Most AI assistants rely on live web retrieval at the moment of the user's question, not pre-indexed crawling.
- DeepSeek
- Chinese AI assistant. Around 4% market share as of mid-2026. Noteworthy for open-weights releases and low API pricing.
- Entity
- A specific business, person, product or concept the AI can identify consistently across sources. Strong entity signals (consistent name, description, services across the web) make the AI confident enough to cite you.
- The strength of an entity's presence across the web. Built through consistent mentions on your site, Google Business Profile, directories, press, podcasts and social. Higher entity authority leads to more AI citations.
- FAQPage Schema
- Structured data markup that tells search engines and AI assistants a page contains a question-and-answer format. One of the highest-leverage schema types for GEO because answers get lifted verbatim.
- Fan-Out (Prompt Fan-Out)
- The practice of expanding one target keyword into dozens of realistic conversational prompts a user might type into an AI. A single keyword like "best creator platform" fans out into "which creator platform has the lowest fees," "is Patreon better than OnlyFans," and so on.
- Gemini (Google)
- Google's AI assistant. Around 27% market share as of mid-2026, second only to ChatGPT. Powers AI Overviews and AI Mode inside Google Search.
- GEO (Generative Engine Optimization)
- The practice of making a business visible inside AI assistants. Covers ChatGPT, Gemini, Claude, DeepSeek, Grok, Perplexity and Copilot. See the full field guide at What is Generative Engine Optimization.
- Grounding
- The process by which an AI assistant ties its response to specific retrieved sources rather than making it up from training data. Grounded responses include citations; ungrounded responses do not.
- Grok (xAI)
- xAI's AI assistant integrated into X (Twitter). Around 2% market share as of mid-2026 but growing on the platform. Known for live-web awareness via X data.
- Hallucination
- An AI response that states something false or fabricated as if it were factual. Grounding and citation reduce hallucination; well-structured source content reduces it further.
- LLM (Large Language Model)
- The underlying machine learning model behind an AI assistant. GPT-5, Claude Opus 4, Gemini 2.5, Grok 4 and DeepSeek V3 are examples. LLM behavior drives all GEO work.
- llms.txt
- An emerging convention (not yet a formal standard) for a file at the root of a website that tells AI crawlers what the site is about, where key pages are, and what content to prioritize. Analogous to robots.txt but for LLMs.
- LLM SEO
- Synonym for GEO. Some practitioners prefer "LLM SEO" to emphasize that AI assistants are LLMs, not search engines. Covers the same practice.
- Meta AI
- Meta's AI assistant integrated into Facebook, Instagram, WhatsApp and Messenger. Significant reach despite being less visible as a standalone product.
- Perplexity
- AI search assistant focused on cited, grounded responses. Around 1 to 2% market share as of mid-2026 but disproportionately influential because every answer cites sources inline.
- Prompt
- The question or instruction a user types into an AI assistant. GEO work targets the prompts your buyers actually type, not the keywords they would type into Google.
- RAG (Retrieval-Augmented Generation)
- The technical architecture most modern AI assistants use. The AI retrieves relevant documents at query time, then generates a response grounded in those documents. GEO is about becoming one of the documents the AI retrieves.
- Rank Tracking (AI)
- Scheduled measurement of how often and how well a business appears in AI responses to a defined prompt set. Replaces or supplements traditional Google keyword rank tracking.
- Schema Markup
- Structured data in JSON-LD format that tells search engines and AI assistants what a page is about. Organization, Service, Product, FAQPage, Breadcrumb and Article are the most important types for GEO.
- Semantic HTML
- Using HTML tags that describe content meaning (article, section, nav, aside, h1-h6) rather than tags that describe appearance. AI assistants parse semantic HTML to understand page structure.
- SEO (Search Engine Optimization)
- The original discipline: ranking in traditional search engine results pages. Google, Bing, DuckDuckGo. Overlaps heavily with GEO and AEO; the signals are mostly shared.
- SERP (Search Engine Results Page)
- The page a search engine returns in response to a query. The ten blue links experience. Being on SERP page one no longer guarantees traffic because AI Overviews often sit above it.
- See Citation Share of Voice.
- Structured Data
- Synonym for schema markup. Machine-readable metadata in JSON-LD, Microdata or RDFa format embedded in HTML.
- Training Data
- The corpus of text an LLM was trained on before deployment. Training data has a cutoff date. Content published after an LLM's cutoff is only visible to the AI through live web retrieval, not from memory.
- Visibility (AI)
- Catch-all term for how often and how prominently a business appears in AI responses. Measured as citation share of voice plus mention frequency plus citation link rate.