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AI SEO Glossary 2026
The complete glossary of AI SEO terms. 59 definitions covering AEO, GEO, llms.txt, AI crawlers, answer engines, schema markup, and the new metrics that matter when AI replaces traditional search. Updated for 2026.
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AI SEO
14 terms
AEO (Answer Engine Optimization)
The practice of optimizing your content to be cited as a source by answer engines like Perplexity, ChatGPT, Google AI Overviews, and Gemini. AEO targets being inside the AI's answer rather than ranking in traditional search results.
GEO (Generative Engine Optimization)
A broader discipline than AEO that includes optimization for any generative AI output — answer engines, chatbots, and AI features. GEO is the umbrella; AEO is a subset focused specifically on answer engines that show citations.
AI Visibility
The frequency and prominence with which AI assistants mention or cite your brand in their answers. Measured as a visibility rate (% of platforms mentioning you for buyer queries) and citation position (1st, 2nd, etc. in source list).
AI Search
Search experiences powered by large language models that generate natural-language answers with citations rather than returning a list of links. Examples: ChatGPT search, Perplexity, Google AI Overviews, Microsoft Copilot, Gemini.
Citation Anchor
A specific, factual statement (often with numbers or named entities) that an AI quotes or paraphrases when citing your page. AEO favors content rich in citation anchors over vague marketing copy.
Answer-First Content
A content structure where the direct answer to a user's question appears in the first 1-2 sentences, followed by elaboration. Optimized for AI extraction — most AI engines pull from the first 100 words.
Comparison Page
A page comparing your product against a specific competitor (e.g., 'Linear vs Asana'). Heavily cited by AI when users ask 'X vs Y' queries. One of the highest-ROI page types for AEO.
Alternative Page
A page targeting 'alternatives to [competitor]' queries. Captures buyers actively considering switching. Cited by AI when users ask 'alternatives to X'.
Use Case Page
A page describing how your product solves a specific problem for a specific audience (e.g., 'CRM for solo founders'). Highly cite-worthy because it matches buyer query phrasing.
Listicle (Best X)
A list-format article (e.g., 'Best 10 CRMs for Startups'). Heavily referenced by AI when users ask 'what's the best X'. Getting included in third-party listicles is one of the strongest AEO signals.
Entity Recognition
The process by which AI identifies that 'Stripe', 'Stripe Inc.', and 'stripe.com' all refer to the same entity. Strong entity recognition (consistent NAP, clear About page, schema.org Organization markup) improves AI citation reliability.
AI Hallucination
When an AI generates inaccurate information (often confidently). Reduces user trust in AI answers. Strong AEO content (citation-friendly facts, structured data, llms.txt) helps reduce hallucinations about your brand.
Prompt Engineering
The practice of crafting AI prompts to get desired outputs. In AEO context, refers to choosing which buyer queries to track for monitoring (e.g., 'best CRM for SaaS startups' vs generic 'CRM').
Tracked Prompt
A specific buyer query that you monitor across AI platforms over time to measure visibility changes. Most AEO tools let you track 10-200 prompts depending on plan.
Answer Engines
17 terms
Answer Engine
A search experience that returns a generated answer with citations rather than a list of links. Examples: Perplexity, ChatGPT search, Google AI Overviews, Microsoft Copilot, Gemini.
Perplexity
A real-time AI answer engine with strong citation behavior. Uses its Sonar model and web search. The most citation-friendly answer engine — high priority target for AEO.
ChatGPT Search
OpenAI's web search feature inside ChatGPT. Uses Bing's index and surfaces citations in responses. Reaches 700M+ users. Optimizing for ChatGPT search is largely the same as optimizing for Bing.
Google AI Overviews
AI-generated summary answers appearing at the top of Google search results. Cite multiple sources directly. Active on 47%+ of commercial-intent queries — pushing organic links below the fold.
Google AI Mode
A dedicated Google search mode that generates conversational AI responses with citations. More expansive than AI Overviews — full answer engine experience inside Google Search.
Gemini
Google's flagship LLM and chat experience. Uses Google Search grounding for current information. Powers AI Overviews, AI Mode, and gemini.google.com chat.
Microsoft Copilot
Microsoft's AI assistant. Uses Bing search for grounding. Integrated into Bing, Edge browser, and Microsoft 365. Optimizing for Copilot largely means optimizing for Bing.
DeepSeek
Chinese-developed open-source LLM that gained rapid global usage in 2025-2026. Doesn't have native web search but is referenced in many AI brand-monitoring tools as a tracked platform.
Claude
Anthropic's flagship LLM. Used directly via claude.ai and through API integrations in many products. Crawls the web via ClaudeBot to inform responses with current information.
Web Search Tool
A capability that lets an LLM fetch real-time web content during a query. Without web search, LLMs respond from training data only (cutoff date). With web search, LLMs cite live sources — critical for current AEO.
Grounding
The technique of attaching real-time web search results to an LLM response so the AI cites factual sources. Used by Gemini (Google Search grounding), ChatGPT (web search), Perplexity (Sonar).
Token
The basic unit of text that LLMs process. Roughly 1 token = 0.75 words. Pricing for AI APIs is usually per token. Relevant for AEO when calculating cost of running brand-monitoring queries at scale.
Context Window
The maximum amount of text an LLM can consider in a single conversation. Modern LLMs have context windows of 128k-2M tokens. Larger windows let AI process more web search results when answering — more potential citation slots.
LLM (Large Language Model)
A neural network trained on massive text data to generate coherent text. Examples: GPT-4, Claude, Gemini, Llama, DeepSeek. The engine behind every answer engine and AI assistant.
Knowledge Cutoff
The date through which an LLM's training data extends. Without web search, LLMs only know about events before their cutoff. With web search grounding, they can cite current information.
RAG (Retrieval-Augmented Generation)
An AI architecture that retrieves relevant documents (via search) and feeds them to an LLM as context for generating an answer. The technical foundation of every answer engine — Perplexity, ChatGPT search, AI Overviews all use RAG.
Vector Embedding
A numerical representation of text that captures semantic meaning. Used in RAG systems to find relevant content. Sites with clear, well-structured content produce stronger embeddings — improving AI retrieval and citation.
AI Crawlers
8 terms
GPTBot
OpenAI's web crawler. Indexes content for ChatGPT to reference. Identified by user-agent 'GPTBot'. Should be allowed in robots.txt for AI visibility — blocking GPTBot prevents ChatGPT from accessing your content.
ClaudeBot
Anthropic's web crawler for Claude. Indexes content to inform Claude's responses. Identified by user-agent 'ClaudeBot' or 'anthropic-ai'. Allow in robots.txt to be referenced by Claude.
PerplexityBot
Perplexity's crawler. Powers Perplexity's real-time citation search. Identified by user-agent 'PerplexityBot'. Critical for AEO since Perplexity is the most citation-heavy answer engine.
Google-Extended
Google's user-agent token specifically for AI training and Gemini grounding. Separate from Googlebot — blocking Google-Extended affects only AI features (Gemini, AI Overviews), not Google Search rankings.
Meta-ExternalAgent
Meta's web crawler for AI products (Meta AI, Llama). Identified by user-agent 'meta-externalagent'. Allow in robots.txt for visibility in Meta's AI assistants.
Applebot-Extended
Apple's AI training crawler. Separate from Applebot (Spotlight/Siri). Blocking Applebot-Extended prevents your content from being used to train Apple Intelligence and Siri's AI features.
Bingbot
Microsoft's primary web crawler. Indexes content for Bing search and powers ChatGPT search (which uses Bing's index). Critical for AI visibility — getting your sitemap into Bing helps both Bing search and ChatGPT.
AI Crawler
A web bot operated by an AI company to index content for use in LLMs or AI search. Examples: GPTBot, ClaudeBot, PerplexityBot, Google-Extended, Meta-ExternalAgent.
Schema & Files
10 terms
llms.txt
A Markdown file at /llms.txt that tells AI crawlers what your product does. Includes product name (H1), tagline, key features, pricing, use cases, and links to important pages. Sites with valid llms.txt are cited 3× more often.
llms-full.txt
An expanded version of llms.txt with full documentation content for AI crawlers. Useful for technical products with extensive docs. Complements (doesn't replace) llms.txt.
robots.txt
A plain-text file at /robots.txt that tells web crawlers which paths they're allowed to access. For AI SEO, must explicitly allow GPTBot, ClaudeBot, PerplexityBot, Google-Extended, and Meta-ExternalAgent.
FAQ Schema (FAQPage JSON-LD)
Structured data markup using schema.org FAQPage type. Lists questions and answers in machine-readable JSON-LD. The #1 most-cited data type by AI crawlers — Q&A pairs map directly to how AI structures responses.
JSON-LD
JavaScript Object Notation for Linked Data. The standard format for embedding structured data (schema.org markup) in web pages via <script type="application/ld+json"> tags. Preferred by Google and AI crawlers over Microdata or RDFa.
Schema.org
A collaborative vocabulary for structured data on the web, sponsored by Google, Microsoft, Yahoo, Yandex. Defines types like Organization, SoftwareApplication, FAQPage, Article, Product. AI crawlers parse schema.org markup to understand page meaning.
Sitemap (XML Sitemap)
An XML file listing all URLs on your site that you want crawlers to discover. Submitted to Google Search Console, Bing Webmaster Tools, and IndexNow. Critical for fast AI crawler discovery of new content.
IndexNow
A protocol for instantly notifying search engines (Bing, Yandex, Naver) about new or updated URLs. One ping reaches multiple engines. Bypasses traditional crawl latency — pages can be indexed within minutes instead of days.
Canonical Tag
An HTML link tag (<link rel="canonical" href="...">) that signals the preferred version of a page when duplicate or similar pages exist. Prevents duplicate content issues and consolidates ranking signals.
Open Graph Tags
Meta tags (og:title, og:description, og:image) that control how URLs appear when shared on social platforms. Some AI search experiences also use Open Graph data for rich previews.
Metrics
5 terms
Citation Rate
The percentage of AI-generated answers in your category that cite your brand or website as a source. A citation rate of 0% means AI never references you; 70%+ means you're consistently in the answer.
Brand Mention
Any reference to your brand name in an AI-generated answer, whether or not the AI cites your URL as a source. Tracked across LLMs as part of AI visibility monitoring.
Visibility Rate
The percentage of AI platforms (out of 7 tracked) that mention your brand for a given buyer query. 70%+ is excellent; below 30% is critical.
Prompt Coverage
The number of distinct buyer queries (prompts) for which AI cites your brand. Higher prompt coverage means AI sees you as relevant across more topics in your category.
SEO Foundations
5 terms
SEO (Search Engine Optimization)
The traditional practice of optimizing content to rank in search engine results pages (SERPs). Different from AEO and GEO, which target AI-generated answers rather than ranked links.
SERP
Search Engine Results Page. The page returned in response to a user's query. In 2026, SERPs increasingly include AI Overviews, featured snippets, and related questions alongside traditional ranked results.
Backlink
A hyperlink from another website to yours. Major ranking factor for traditional SEO. Less direct impact on AEO — AI weighs content quality and entity recognition more than backlink graphs.
Crawl Budget
The number of pages a search engine bot will crawl on your site within a given timeframe. Important for large sites — wasted crawl budget on low-value pages reduces discovery of important content.
EEAT
Experience, Expertise, Authoritativeness, Trust. Google's quality framework for evaluating content. Applies to both SEO and AEO — AI engines also weigh authority signals when choosing sources to cite.
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