Skip to content
RankX AI
Start Free TrialFree Trial

AI Search Visibility Platform

The vocabulary of AI search, defined and dated.

The RankX AI glossary defines the words AI search runs on, from crawlers to whether ChatGPT, Claude, Gemini, Grok and Perplexity name you. Every entry names its source and date.

68 terms, A to Z, and more as they are researched. Each definition opens with the term and runs to 40 to 60 words, so a quote survives with none of the page around it. Where a source is contested or a fact undocumented, the entry says so instead of choosing.

A

  • AI Brand SentimentMetricAI brand sentiment is how favourably an AI assistant describes a brand when it names one: recommended, listed neutrally, or named as the option to avoid.
  • AI CitationMetricAn AI citation is a link an AI assistant attaches to its answer, naming a page as a source.
  • AI CrawlerThe AI layerAn AI crawler is an automated fetcher run by an AI company to collect web pages.
  • AI HallucinationThe AI layerAn AI hallucination is a statement a language model produces confidently and fluently that is not true.
  • AI MentionMetricAn AI mention is your brand name appearing in the text of an AI assistant’s answer, whether or not the answer links to you.
  • AI OverviewCategory termAn AI Overview is the written summary Google places above its ordinary search results, assembled from web pages and shown with links to a few of them.
  • AI Referral TrafficThe AI layerAI referral traffic is the visits that arrive at a site from an AI assistant rather than from a search results page.
  • AI Share of VoiceMetricAI share of voice is the proportion of AI answers naming your brand, measured across a panel of tracked prompts and compared against the rivals named in the same answers.
  • Answer BlockThe AI layerAn answer block is a short passage near the top of a page that answers the page’s question completely and on its own.
  • Answer EngineCategory termAn answer engine is a search product that returns a written answer rather than a ranked list of links, citing a handful of sources inside it.
  • Answer Engine Optimization (AEO)Category termAnswer Engine Optimization is the practice of writing pages so an AI assistant can lift a direct answer out of them.
  • Atomic ContentThe AI layerAtomic content is the practice of writing in self-contained units, each covering one idea completely enough to be understood alone.

B

  • BLUF (Bottom Line Up Front)The AI layerBLUF, or bottom line up front, is the convention of stating the conclusion in the opening sentence and the supporting reasoning afterwards.

C

  • Canonical TagSEO fundamentalsA canonical tag is a link element naming the preferred URL for a page when the same content is reachable at more than one address.
  • CCBot (Common Crawl)AI crawlerCCBot is the crawler run by Common Crawl, a non-profit that publishes an open archive of the web for anyone to analyse.
  • ChatGPT-UserAI crawlerChatGPT-User is the agent that fetches a page because a ChatGPT user asked about it, rather than as part of a crawl.
  • ChunkingRetrieval mechanicsChunking is the step that splits a page into passages so a retrieval system can select one without the rest.
  • Citation RateMetricCitation rate is the share of tracked AI answers that link your site as a source, counted over the answers where a source list was actually returned.
  • ClaudeBotAI crawlerClaudeBot is Anthropic’s training crawler, documented as collecting web content that can contribute to training its models.
  • Context WindowThe AI layerA context window is all the text a language model can reference when generating a response, including the response itself.
  • Core Web VitalsSEO fundamentalsCore Web Vitals are Google’s three measurements of real-user page experience: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness, and Cumulative Layout Shift for visual stability.
  • Crawl BudgetSEO fundamentalsCrawl budget is the amount of crawling an engine will do on a site, set by what the server can take and by how much the engine wants the content.

D

  • Digital PRSEO fundamentalsDigital PR is the practice of earning coverage on other people’s websites, historically to acquire backlinks.
  • Domain Rating (DR)SEO fundamentalsDomain Rating is Ahrefs’ score, from 0 to 100, for the strength of a website’s backlink profile relative to every other site in its index.

E

  • E-E-A-TSEO fundamentalsE-E-A-T stands for experience, expertise, authoritativeness and trustworthiness, a framework from Google’s search quality rater guidelines.
  • EmbeddingRetrieval mechanicsAn embedding is a list of numbers representing a piece of text, positioned so that texts with similar meaning sit close together.
  • Entity (SEO)SEO fundamentalsAn entity is a distinct thing a search system has identified and can reason about: a company, a person, a product, a place.

F

  • Featured SnippetSEO fundamentalsA featured snippet is a passage Google extracts from a page and displays at the top of its results, with a link to the source.

G

  • Generative Engine Optimization (GEO)Category termGenerative Engine Optimization is the practice of writing and structuring pages so AI assistants retrieve and cite them.
  • Google AI ModeCategory termGoogle AI Mode is a conversational search surface where a written answer replaces the ranked results page rather than sitting above it.
  • Google-ExtendedAI crawlerGoogle-Extended is a robots.txt token, not a crawler.
  • GPTBotAI crawlerGPTBot is OpenAI’s training crawler.
  • GroundingRetrieval mechanicsGrounding is the step that ties a model’s answer to sources it retrieved, so the reply can cite them rather than assert them.

H

  • Hallucinated URLThe AI layerA hallucinated URL is a link an AI assistant produces that looks plausible and has never existed.

I

  • Information GainThe AI layerInformation gain is how much new information a document adds beyond what a reader has already seen elsewhere.
  • Internal LinkingSEO fundamentalsInternal linking is the practice of linking your own pages to each other with descriptive anchor text.

K

  • Keyword DifficultySEO fundamentalsKeyword difficulty is a vendor’s estimate, usually on a 0 to 100 scale, of how hard it would be to rank on the first page for a keyword.
  • Knowledge CutoffThe AI layerA knowledge cutoff is the date after which a model’s training data contains nothing.
  • Knowledge GraphSEO fundamentalsThe Knowledge Graph is Google’s database of entities and the relationships between them: people, companies, places, works and the facts connecting them.
  • Knowledge PanelSEO fundamentalsA Knowledge Panel is the information box Google shows beside or above its results for an entity it has identified, assembled from the Knowledge Graph rather than from any one website.

L

  • LLMO (Large Language Model Optimization)Category termLLMO, or Large Language Model Optimization, is a third name for the practice of getting a brand cited by AI assistants.
  • llms.txtThe AI layerllms.txt is a proposed file at a site’s root that lists its important pages in markdown, so an AI agent can find them without parsing the site.
  • Long-Tail KeywordSEO fundamentalsA long-tail keyword is a longer, more specific search phrase with lower individual volume than a head term.

O

  • OAI-SearchBotAI crawlerOAI-SearchBot is the crawler that builds the index behind ChatGPT search.

P

  • People Also Ask (PAA)SEO fundamentalsPeople Also Ask is the expanding box of related questions Google shows within its results, each opening to reveal an extracted answer and a source link.
  • PerplexityBotAI crawlerPerplexityBot is the crawler behind Perplexity’s search results.
  • Pillar PageSEO fundamentalsA pillar page is the broad page at the centre of a topic cluster, covering a subject widely and linking out to the deeper pages that cover its parts.
  • Prompt VolumeMetricPrompt volume is how often people put a particular question to an AI assistant, the assistant-side equivalent of search volume.

Q

  • Query Fan-OutRetrieval mechanicsQuery fan-out is Google’s own term for how AI Overviews and AI Mode answer a question: the engine breaks the question into subtopics and issues many searches at once, then writes one answer from the results.

R

  • RAG (Retrieval-Augmented Generation)Retrieval mechanicsRAG, or retrieval-augmented generation, is the technique of fetching documents at question time and giving them to a language model to answer from, rather than relying on what the model learned in training.
  • Referring DomainSEO fundamentalsA referring domain is a unique website that links to yours at least once, however many individual links it sends.
  • Robots.txtSEO fundamentalsRobots.txt is a file at a site’s root telling automated crawlers which paths they may fetch.

S

  • Schema Markup (Structured Data)SEO fundamentalsSchema markup is structured data added to a page in the schema.org vocabulary, usually as JSON-LD, describing what the page is about in a form machines can parse.
  • Search IntentSEO fundamentalsSearch intent is what a person actually wants when they type a query, as distinct from the words they used.
  • Search VolumeSEO fundamentalsSearch volume is an estimate of how often a keyword is searched in a given period, usually per month and per country.
  • Semantic SearchThe AI layerSemantic search retrieves results by meaning rather than by matching the words a searcher typed.
  • SERPSEO fundamentalsA SERP is a search engine results page: everything an engine returns for a query, including the organic links, the ads and the features above and between them.
  • Server-Side Rendering (SSR)SEO fundamentalsServer-side rendering means a page’s HTML arrives from the server already containing its content, rather than being assembled in the browser by JavaScript.
  • Synthetic QueryThe AI layerA synthetic query is a search an engine writes itself, generated from a user’s question rather than typed by anyone.

T

  • Temperature (LLM)The AI layerTemperature is the parameter controlling how much randomness a language model injects into its response.
  • Token (LLM)The AI layerA token is the unit a language model processes text in: a fragment that may be a whole word, part of one, a space or a punctuation mark.
  • Topic ClusterSEO fundamentalsA topic cluster is a group of pages covering one subject: a broad pillar page and the deeper pages that link up to it and across to each other.
  • Topical AuthoritySEO fundamentalsTopical authority is the idea that covering a subject deeply and consistently makes a site more likely to rank across it.
  • Training DataThe AI layerTraining data is the body of text a language model learns from before it answers anything.

U

  • Unlinked Brand MentionSEO fundamentalsAn unlinked brand mention is a reference to your brand in someone else’s content with no hyperlink attached.

V

  • Vector SearchThe AI layerVector search finds documents by comparing embeddings rather than by matching words: each passage is stored as a list of numbers, and a query is answered by finding the nearest ones.

X

  • XML SitemapSEO fundamentalsAn XML sitemap is a file listing the URLs on a site that you want search engines to know about, optionally with the date each was last modified.

Z

  • Zero-Click SearchThe AI layerA zero-click search is a search that ends without the searcher clicking through to any website.

Back to the top

Start here

See where you show up in AI answers today.

Add your site and RankX AI suggests the prompts to track, monitors the keywords that matter and audits your pages, with your first results minutes after you finish setup.

Start Free Trial

7-day free trial. No credit card required. Cancel anytime.