69 terms · Updated September 21, 2026
The AI search glossary
Every term you need for SEO, GEO and AI visibility — defined in one sentence, then explained for teams that have to act on it. Sourced, dated, and written to be quoted.
Start here
New to AI search? Read these six, in order.
- 01Search engine optimizationThe index every AI engine retrieves from
- 02Generative engine optimizationEarning a place inside the answer
- 03Retrieval-augmented generationHow engines fetch sources before writing
- 04Query fan-outWhy one question becomes many searches
- 05AI citationWhat winning looks like
- 06AI share of voiceHow to measure it against competitors
All 69 terms, A to Z
A
- AI search & GEOAI citationA link or source reference that an AI answer engine attaches to its response to show where a claim came from, and it differs from a brand mention in that it points to a specific page that can be clicked and can send traffic.
- AI crawlersAI crawlersAutomated bots run by AI companies that fetch web pages for one of three jobs — training models, building an AI search index, or retrieving a page live for a user’s question — and because each job uses its own user agent, each can be allowed or blocked separately.
- How LLMs answerAI hallucinationA confident but false statement produced by a large language model — an invented statistic, feature, price or citation — which happens because the model generates plausible text rather than looking facts up.
- AI search & GEOAI ModeA conversational search experience inside Google Search that answers complex questions with a generated response built from many parallel sub-searches and supports follow-up questions, rather than summarizing above the classic results as AI Overviews do.
- AI search & GEOAI OverviewsAI-generated summaries shown at the top of some Google search results, written by a Gemini model from pages in Google’s search index and linked to their sources — so they are won through ordinary Google eligibility, not a separate submission or special markup.
- MeasurementAI referral trafficThe visits a website receives from links inside AI assistants and answer engines such as ChatGPT, Perplexity, Gemini, Claude and Copilot, identified in analytics by referrer domains like chatgpt.com and perplexity.ai.
- AI search & GEOAI search engineA search product that answers a query with a response written by a large language model, grounded in web pages it retrieves and usually citing them, instead of returning a ranked list of links for the user to open.
- MeasurementAI share of voiceThe percentage of AI-generated answers, across a fixed set of relevant prompts, that mention or cite a brand compared with its competitors — the AI-search version of the classic measure of a brand’s share of the market conversation.
- AI search & GEOAI visibilityA measure of how often, how prominently and how favorably a brand appears in answers from AI systems such as ChatGPT, Perplexity, Gemini and Google AI Overviews for the questions its buyers ask — the AI-search counterpart to search rankings.
- Authority & off-siteAnchor textThe visible, clickable text of a link, which search engines read as a description of the page it points to — so natural, descriptive anchors help, while the same exact-match keyword repeated across many sites looks manipulative.
- AEOAI search & GEOAnswer engine optimizationThe practice of structuring content as direct, extractable answers so that systems which return one answer — featured snippets, voice assistants and AI chatbots — use it as the answer itself rather than listing it as one link among ten.
- Content & relevanceAnswer-first contentA writing structure that puts the direct answer to a section’s question in its opening sentence and adds context and evidence after it, so readers and AI retrieval systems can take the answer without reading further.
B
- Authority & off-siteBacklinksA link from one website to another, which search engines treat as a vote of confidence that passes authority to the page it points to — and the relevance and quality of the linking site matter far more than the number of links.
- Authority & off-siteBrand mentionsAny reference to a brand’s name on another website, forum, review site or video, with or without a link, and in large studies mentions correlate more strongly with visibility in AI answers than backlinks do.
C
- Technical SEOCanonical tagAn HTML link element (rel="canonical") that tells search engines which URL is the preferred version of a page reachable at several addresses, consolidating its ranking signals onto that one URL — a strong hint, not a command.
- AI crawlersClaudeBotAnthropic’s crawler for collecting web content that may be used to train Claude models, one of three Anthropic bots alongside Claude-SearchBot, which indexes pages for Claude’s search results, and Claude-User, which fetches pages when a user asks.
- CTRMeasurementClick-through rateThe percentage of people who click a result after seeing it — clicks divided by impressions — and in search it is falling for many queries as AI Overviews and other answer features resolve the question on the results page.
- How LLMs answerContent chunkingThe splitting of a page into smaller passages — often a heading and the text beneath it — that an AI retrieval system indexes, scores and quotes individually, which makes the section, not the whole page, the unit that competes for a citation.
- Content & relevanceContent decayThe gradual loss of rankings, traffic and AI citations a page suffers as its information ages, competitors publish better answers or intent shifts — a predictable decline fixed by refreshing, consolidating or retiring the page.
- Content & relevanceContent freshnessHow recently a page was substantively created or updated, which search engines weigh for time-sensitive queries and most AI answer engines appear to weigh even more — the pages they cite are measurably newer than classic search results.
- CWVTechnical SEOCore Web VitalsGoogle’s three field metrics for page experience — Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness and Cumulative Layout Shift for visual stability — measured from real Chrome users and used as a modest ranking signal.
- Technical SEOCrawl budgetThe number of URLs a search engine is willing and able to crawl on a site in a given period, set by how much load the server can take and how much the engine wants the content — a real constraint mainly for large or fast-changing sites.
D
- Authority & off-siteDigital PRThe practice of earning coverage, links and mentions from news sites, publications and industry blogs by giving journalists something worth reporting — original data, expert comment, a story — which builds both backlinks and the brand mentions AI models learn from.
- DAAuthority & off-siteDomain authorityA third-party score from 1 to 100, created by Moz, that predicts how well a website is likely to rank based mainly on its backlinks; Google does not use it, and comparable metrics include Ahrefs’ Domain Rating and Semrush’s Authority Score.
E
- Authority & off-siteE-E-A-TThe framework Google’s search quality raters use to judge whether content is credible, with trust at its center; it is not a single ranking factor but a description of what Google’s systems aim to reward.
- Authority & off-siteEntity SEOThe practice of making search engines and AI models recognize a brand, person or product as a distinct, well-described thing — an entity with consistent facts and relationships — rather than a string of keywords, so it can be tied to the topics it should be recommended for.
F
G
- GEOAI search & GEOGenerative engine optimizationThe practice of making content easy for AI answer engines such as ChatGPT, Perplexity and Google AI Overviews to retrieve, quote and cite — where SEO competes for a ranked link, GEO competes to be a named source inside the generated answer.
- GSCMeasurementGoogle Search ConsoleGoogle’s free tool for site owners that reports how a site performs in Google Search — queries, impressions, clicks, position and indexing — and since 2026 it also reports impressions in Google’s generative AI features and lets owners opt out of them.
- AI crawlersGoogle-ExtendedA robots.txt product token, not a separate crawler, that lets site owners stop Google from using their content to train Gemini models and to ground answers in the Gemini app, without affecting Google Search — including AI Overviews and AI Mode.
- AI crawlersGPTBotOpenAI’s web crawler for collecting content that may be used to train its AI models; blocking it in robots.txt opts a site out of training but does not remove it from ChatGPT search, which uses a separate crawler, OAI-SearchBot.
- How LLMs answerGroundingThe process of tying an AI model’s answer to specific, verifiable sources — usually web pages retrieved at the moment of the question — so the claims in the response can be checked and cited, rather than generated from the model’s memory alone.
I
- Technical SEOIndexingThe step in which a search engine processes a crawled page and stores it in its searchable database; only indexed pages can rank, or be retrieved for AI answers built on that index, and being crawled does not guarantee being indexed.
- Technical SEOIndexNowAn open protocol that lets a website notify participating search engines, led by Microsoft Bing, the moment a URL is added, updated or deleted, instead of waiting to be recrawled — Google does not use it.
- Content & relevanceInformation gainThe new information a page adds beyond what other pages on the same topic already say — original data, first-hand experience, a new angle — and it is the leading explanation for why content that rewrites the top results struggles to rank or be cited.
- Authority & off-siteInternal linkingThe practice of linking between pages on the same website, which helps crawlers find pages, moves authority from strong pages to weaker ones and shows search engines and AI systems how the topics on a site relate.
K
- Content & relevanceKeyword cannibalizationWhen two or more pages on the same site target the same query and intent, splitting links and relevance so search engines rotate between them or rank neither as well as one consolidated page would.
- KDMeasurementKeyword difficultyA third-party estimate, usually on a 0 to 100 scale, of how hard it would be to reach Google’s first page for a query, calculated mostly from the backlink strength of the pages already ranking — useful for choosing winnable topics, but not a Google metric.
- How LLMs answerKnowledge cutoffThe date after which a large language model has no information from its training data, so anything newer — a launch, a price change, a new competitor — reaches its answers only if the model retrieves it from the live web.
- Authority & off-siteKnowledge GraphA database of hundreds of billions of facts about entities — people, places, organizations and products — and the relationships between them, which Google uses to understand queries, fill knowledge panels and help its AI features tell one brand from another.
L
- LLMHow LLMs answerLarge language modelA neural network trained on vast amounts of text to predict the next word, which lets it write fluent answers — the technology behind ChatGPT, Claude and Gemini, whose knowledge is fixed at training time unless it retrieves fresh sources.
- AI search & GEOLLM SEOThe practice of making a brand visible in the responses of large language models such as ChatGPT, Claude and Gemini, covering both what a model says from its training data and what it cites when it searches the live web.
- How LLMs answerLLM training dataThe body of text — web crawls, books, code, licensed and forum content — that a language model learns from before release, and it shapes what the model says about a brand without searching, in a way that can’t be edited until the next model is trained.
- AI crawlersllms.txtA proposed standard for a Markdown file, usually at a site’s root, that gives large language models a curated map of a site’s key pages; unlike robots.txt it grants or blocks nothing, and no major AI search engine has confirmed using it.
- Content & relevanceLong-tail keywordsSpecific search phrases that each draw few searches but together make up the vast majority of distinct queries, and because they signal precise intent they are the closest classic-SEO match to the conversational prompts people type into AI.
M
O
P
- AI crawlersPerplexityBotPerplexity’s crawler for indexing web pages so they can be surfaced and cited in Perplexity’s answers — Perplexity says it is not used to train foundation models — while a separate agent, Perplexity-User, fetches pages live when a user asks.
- pSEOContent & relevanceProgrammatic SEOThe practice of generating many landing pages from a template and a structured dataset — one page per city, integration or comparison — to target a large set of similar long-tail queries, and it works only when each page carries unique, useful data.
- MeasurementPrompt trackingThe practice of running a fixed set of buyer questions through AI assistants such as ChatGPT, Perplexity and Gemini on a schedule and recording which brands and pages each answer mentions or cites — the AI-search equivalent of rank tracking.
Q
R
- Authority & off-siteReddit SEOThe practice of earning a brand’s place in Reddit threads that rank in Google and feed AI answers, by contributing genuinely useful replies in relevant communities rather than posting promotions, which Reddit’s rules and moderators remove.
- How LLMs answerRerankingA second retrieval stage in which a more precise model re-scores the top results of a first, faster search against the query and reorders them — the step that decides which few passages an AI answer engine actually reads and cites.
- RAGHow LLMs answerRetrieval-augmented generationA technique in which an AI system first retrieves relevant documents from an index and then gives them to a large language model to write its answer, so the response can cite current sources instead of relying only on what the model memorized in training.
- AI crawlersrobots.txtA plain-text file at a site’s root that tells crawlers which paths they may fetch, rule by rule for each user agent — a voluntary standard that reputable search and AI bots follow, which controls crawling but not whether a URL gets indexed.
S
- Content & relevanceScaled content abuseGoogle’s spam-policy term for producing many pages mainly to manipulate search rankings rather than to help people — whether by AI, templates or hand — and it targets the purpose and value of the content, not the use of AI itself.
- Technical SEOSchema markupStructured data, usually written as JSON-LD with the Schema.org vocabulary, that labels what a page contains — an article, a product, an organization, a local business — so search engines can interpret it unambiguously and show it as rich results.
- SEOAI search & GEOSearch engine optimizationThe practice of improving a website’s content, technical setup and authority so search engines crawl, index and rank it for relevant queries — and because most AI answer engines retrieve their sources from a search index, it is also the foundation of AI visibility.
- Content & relevanceSearch intentThe goal behind a query — to learn something, reach a specific site, compare options or buy — and matching it decides which kind of page, from a guide to a product page to a comparison, search engines and AI answers treat as relevant.
- How LLMs answerSemantic searchA retrieval method that matches a query to content by meaning and intent — typically by comparing vector embeddings — instead of by the exact words both contain, so a page can be found for phrasings it never uses.
- MeasurementSERPThe page a search engine returns for a query, which today mixes classic blue links with AI Overviews, ads, featured snippets, videos, forum threads and other features competing for the same attention.
- SSRTechnical SEOServer-side renderingThe practice of generating a page’s full HTML on the server before sending it, so crawlers that don’t run JavaScript — which includes most AI crawlers — can read the content in the first response.
- Technical SEOSnippet controlsRobots directives and HTML attributes — nosnippet, max-snippet and data-nosnippet — that limit how much of a page search engines may quote in results, and in Google they also limit what AI Overviews and AI Mode can use.
T
- Content & relevanceTitle tagThe HTML title element that names a page for browsers, search results and AI retrieval, and it is the main source Google draws on for a result’s title link — though Google may rewrite that link when the tag is missing, stuffed or mismatched to the page.
- Content & relevanceTopic clusterA group of interlinked pages on one subject — a broad pillar page linked to and from narrower pages on each subtopic — built to show search engines and AI retrieval systems complete coverage of the topic rather than a single article.
- Authority & off-siteTopical authorityThe degree to which search engines and AI systems treat a site as a reliable source on a whole subject, earned by covering that subject in depth and being referenced for it elsewhere, rather than by ranking for any one keyword.
V
X
Z
Start here
New to AI search? Read these six, in order.
- 01Search engine optimizationThe index every AI engine retrieves from
- 02Generative engine optimizationEarning a place inside the answer
- 03Retrieval-augmented generationHow engines fetch sources before writing
- 04Query fan-outWhy one question becomes many searches
- 05AI citationWhat winning looks like
- 06AI share of voiceHow to measure it against competitors
Browse by topic
Seven areas, from how answer engines work to how you measure them.
AI search & GEO
The disciplines and the surfaces: SEO, GEO, AEO, and where AI answers appear.
How LLMs answer
How language models retrieve, rank and ground the sources they cite.
AI crawlers
The bots that read your site, what each one does, and how to control them.
Technical SEO
Rendering, indexing and markup: whether engines can read the page at all.
Content & relevance
What makes a page the best answer to a question, and keeps it that way.
Authority & off-site
Links, mentions and entities: why engines trust one source over another.
Measurement
How to see whether search and AI engines rank, cite and send you traffic.
FAQ
Questions about the vocabulary
What's the difference between SEO, GEO and AEO?
SEO earns rankings in search results, AEO formats content so it can be used as a direct answer, and GEO earns citations inside AI-generated answers. All three rest on the same foundation — crawlable, indexed, genuinely useful pages — so they’re layers of one job, not three competing strategies.
What does LLM SEO mean?
LLM SEO is making a brand visible in what large language models say — both from their training data and from the pages they cite when they search the web. It’s the model-centric name for the same work GEO describes.
Which AI crawlers should I allow?
Allow each engine’s search and user-triggered bots — OAI-SearchBot and ChatGPT-User, Claude-SearchBot and Claude-User, PerplexityBot and Perplexity-User — and decide on training crawlers such as GPTBot, ClaudeBot and Google-Extended separately. Blocking a training crawler doesn’t remove you from that engine’s search.
How is this glossary kept accurate?
Every entry is dated and cites its sources, and the original frameworks are labelled as ours. Entries on fast-moving topics — crawlers, engine behavior, analytics — are re-checked every quarter, and an entry’s updated date changes only when its facts are re-verified.
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