GEO (Generative Engine Optimization) is the set of practices that get a site cited in answers generated by ChatGPT, Gemini, Perplexity and Google AI Overviews. This glossary defines the 114 terms that structure this field in 2026, from query fan-out to chunking, from grounding to embeddings. Each definition fits in one or two sentences, with its French equivalent and its dedicated page.
A
AEO (Answer Engine Optimization)
AEO (Answer Engine Optimization)
Synonym of GEO: optimization to be selected as the answer by an answer engine rather than as a link in a results list. No consensus definition separates it from GEO.
Full definition →Agent-friendly website
Agent-friendly website
An agent-friendly website is a site designed to be used by browser-based AI agents, which read the visual rendering, the DOM structure and the accessibility tree to complete a task. Google points to a web.dev best-practices guide and describes this field as emerging and evolving.
Full definition →Agentic commerce
Agentic commerce
Purchase made by an AI agent on behalf of a user. Requires exposing price, stock and availability in plain HTML and in structured data.
Full definition →AI answer volatility
Volatilité
Instability of AI answers from one run to the next for the same prompt. Requires measuring over repeated series.
Full definition →AI citation
Citation IA
Mention of a source, with a link, in an AI-generated answer. The unit of visibility in GEO, the functional equivalent of position one in classic SEO.
Full definition →AI crawler
Crawler IA
Bot of an LLM provider (GPTBot, ClaudeBot, PerplexityBot, Google-Extended). Blocking a search bot in robots.txt excludes the site from the matching generative answers.
Full definition →AI impression
Impression IA
Display of a URL in an AI surface, counted in Search Console with no distinction between AI Overviews and AI Mode.
Full definition →AI Knowledge Panel
AI Knowledge Panel
An AI Knowledge Panel is an entity card displayed by an AI assistant, such as ChatGPT’s clickable entities, presenting a recognized brand, place or person. It brings assistants closer to Google’s Knowledge Panel and makes entity recognition decisive.
Full definition →AI Mode
AI Mode (mode IA)
Google’s conversational search surface, alongside the Images or News tabs. Activated by the user, it relies on query fan-out to produce in-depth answers with follow-ups.
Full definition →AI Overviews
AI Overviews
AI-generated summary shown at the top of a classic Google results page, with a few source links. Formerly Search Generative Experience (SGE). Available in France since July 22, 2026.
Full definition →AI position
AI position
AI position is the average rank at which a brand is cited in generated answers when it appears: 1 for a brand named first, 5 for fifth place. It measures order within the answer, not a ranking of pages.
Full definition →AI recommendation
AI recommendation
An AI recommendation is when a generative engine explicitly proposes a brand or product as a choice in its answer. It differs from a citation, which designates a linked source: a page can be cited without the brand being recommended.
Full definition →AI referral traffic
AI referral traffic
AI referral traffic refers to visits that reach a site from an AI assistant or engine, through a cited link. It is identified in analytics by the referral source, and Microsoft Clarity exposes its trends in its Citations dashboard.
Full definition →AI response
AI response
An AI response is the text an engine generates after processing a prompt, sometimes accompanied by sources, links or brand recommendations. It is the object GEO tools collect and analyze, and it can change with every run.
Full definition →AI sentiment
Sentiment IA
Tone (positive, neutral, negative) with which a brand is mentioned in AI answers. Measured by GEO tools, with variable reliability.
Full definition →AI Share of Voice
Share of Voice IA
Share of AI answers, over a set of prompts, in which a brand is cited relative to its competitors. The core metric of GEO reporting.
Full definition →AI visibility
AI visibility
AI visibility measures how often a brand is mentioned or its site cited in AI engines’ answers, over a given prompt corpus. It is the overall GEO indicator, broken down into brand visibility, source visibility, position and share of voice.
Full definition →Answer-first
Answer-first
Editorial structure that puts the direct answer at the top of a section, before any context. AI citation analyses show that passages of 40 to 75 words answering the heading’s question immediately are the most reused.
Full definition →B
Bing AI Performance
AI Performance (Bing)
Bing Webmaster Tools report opened in February 2026, exposing citations, a sample of grounding queries and, since June 2026, Citation Share.
Full definition →BM25
BM25
BM25 is a lexical ranking function that scores a document by the frequency of the query’s terms, weighted by their rarity and the document’s length. It is the basis of sparse retrieval, often combined with vector search in hybrid search systems.
Full definition →Brand mention
Mention de marque
Naming of a brand in an AI answer, with or without a link. A mention without a link counts for visibility but sends no traffic.
Full definition →C
Canonical tag
Balise canonical
Tag indicating the reference URL among several versions of the same content. Consolidates signals on a single page.
Full definition →ChatGPT Memory
ChatGPT Memory
ChatGPT’s memory is the feature that lets the assistant retain preferences and information from past conversations, saved memories or other sources in order to personalize its answers. It differs from parametric memory, acquired when the model is trained.
Full definition →Chunking
Chunking
Splitting a page into semantically coherent passages before vector indexing. Each chunk is then scored independently: a page can be ignored overall but cited for a single paragraph.
Full definition →Citability
Citabilité
A page’s propensity to be cited by an AI engine. Strengthened by original data, dated figures, named sources and an extractable structure.
Full definition →Citation capsule
Citation capsule
Standalone, factual, dated and sourced block designed to be cited as is by a generative engine without interpretation. A practitioner term, not an official standard.
Full definition →Citation Share
Citation Share
Share of citations attributed to a site out of all citations shown for a grounding query. Specific to Bing’s AI Performance report.
Full definition →CiteMET
CiteMET
CiteMET (Cited, Memorable, Effective, Trackable) is a method promoted by LLMrefs that adds share buttons to pages that open AI assistants with a prefilled prompt. Its effectiveness has not been independently demonstrated, and it comes close to techniques Microsoft has described as recommendation poisoning.
Full definition →Clarity AI Citations
Microsoft Clarity Citations
Clarity AI Citations is the Microsoft Clarity dashboard that shows how content is cited in AI-generated answers. Available to all Clarity projects since May 2026, it exposes cited pages, grounding queries, share of authority and AI-referred traffic trends.
Full definition →Click-through rate (CTR)
Click-through rate
The CTR is the percentage of impressions that result in a click. With AI summaries it often drops even when positions hold: Pew Research finds a click on a traditional result in 8% of visits when an AI summary appears, versus 15% without.
Full definition →Client-Side Rendering (CSR)
CSR
Content generation by JavaScript in the browser. Risky for GEO, because the initial HTML delivered to AI crawlers is almost empty.
Full definition →Common Crawl
Common Crawl
Common Crawl is a non-profit foundation that maintains a free, open repository of web crawl data, used as a source of training data by many language models. Its crawler is called CCBot.
Full definition →Content freshness
Content freshness
Content freshness refers to how recent a page and its information are, which engines may take into account, especially on evolving topics. GEO tools observe a recency bias in AI citations, whose exact size varies across studies.
Full definition →Context window
Fenêtre de contexte
Maximum amount of text a model can process at once. Limits how many sources an AI engine can cross-check in an answer.
Full definition →Core Web Vitals
Core Web Vitals
Three loading and interaction experience metrics measured by Google: LCP (main content display), CLS (visual stability) and INP (responsiveness to interactions).
Full definition →Cosine similarity
Cosine similarity
Cosine similarity is a measure of closeness between two vectors, based on the angle between them rather than their length. In GEO, it is used to compare a query’s embedding with that of a passage or page to estimate how close they are in meaning.
Full definition →Crawl
Crawl
Automated traversal of a site by a bot to discover and fetch its pages. Absolute prerequisite: a page that is not crawled is neither indexed nor cited.
Full definition →Crawl budget
Crawl budget
Number of pages a search engine agrees to crawl on a site within a given time. Only a concern for very large sites.
Full definition →D
Deep Search
Deep Search
In-depth mode of Google AI Mode that pushes query fan-out to several hundred sub-queries to produce a sourced report.
Full definition →DefinedTerm
DefinedTerm
Schema.org type describing a term and its definition. Reference type for an individual glossary page.
Full definition →DefinedTermSet
DefinedTermSet
Schema.org type describing a set of defined terms: glossary, dictionary, taxonomy. Reference type for a glossary hub page.
Full definition →Dense retrieval
Dense retrieval
Document retrieval based on dense embeddings, as opposed to sparse retrieval based on term frequency (BM25, TF-IDF).
Full definition →E
E-E-A-T
E-E-A-T
Quality evaluation framework from Google’s Quality Rater Guidelines. In GEO, it translates into identified authors, named sources and dated data.
Full definition →Embedding
Embedding
Vector representation of a text in a mathematical space, where closeness between vectors reflects closeness in meaning. Basis of semantic search and RAG.
Full definition →Entity
Entité
Uniquely identifiable object (person, brand, place, concept), distinct from the string that names it. LLMs reason in entities and relationships, not keywords.
Full definition →F
FAQPage
FAQPage
Schema.org type marking up a series of questions and answers. Google stopped showing the rich result on May 7, 2026, but the markup still feeds entity understanding.
Full definition →FastSearch
FastSearch
Google’s accelerated retrieval system, faster than the classic algorithm but consulting fewer sources. Used to ground Gemini’s answers and to generate AI Overviews.
Full definition →G
Generative AI report
Rapport IA générative (GSC)
Search Console report launched on June 3, 2026, isolating AI Overviews and AI Mode impressions. No clicks, no CTR, no queries so far.
Full definition →Generative Engine Optimization (GEO)
GEO (Generative Engine Optimization)
Practices that get a site cited and recommended in answers from AI engines (ChatGPT, Gemini, Perplexity, AI Overviews). Used interchangeably with AEO, LLMO and AI SEO.
Full definition →Grounding
Grounding
Anchoring an LLM’s answer in verifiable web sources rather than in its parametric memory alone. Reduces hallucinations and determines whether citations appear.
Full definition →Grounding query
Grounding query
Query sent by an AI engine to a search index to ground its answer. Bing Webmaster Tools exposes a sample in its AI Performance report.
Full definition →H
Hallucination
Hallucination
False statement produced with confidence by an LLM. Frequent when the model answers from parametric memory without grounding, or when retrieved sources are poor.
Full definition →Hreflang
Hreflang
Attribute signaling equivalent language or regional versions of a page. Poorly implemented, it causes cannibalization between markets.
Full definition →I
Indexing
Indexation
Recording of a page in a search engine’s index after crawling and rendering. A crawled page is not necessarily indexed.
Full definition →IndexNow
IndexNow
IndexNow is a protocol that lets a site notify participating engines as soon as a URL is added, updated or deleted, instead of waiting for their next visit. Engines that adopt it share submissions with each other. The protocol’s documentation does not list Google among the participants.
Full definition →Internal linking
Maillage interne
Network of links between pages of the same site. Structures understanding of relationships between concepts, for engines and AI systems.
Full definition →ISR (Incremental Static Regeneration)
ISR
Periodic regeneration of static pages, specific to Next.js. A compromise between content freshness and delivery performance.
Full definition →J
JSON-LD
JSON-LD
Format for implementing structured data, injected in a script tag. The format preferred by Google over Microdata and RDFa.
Full definition →K
Keyword cannibalization
Cannibalisation
When several pages on a site target the same intent, diluting signals. In GEO, it also blurs the passage the engine should retain.
Full definition →Knowledge cutoff
Knowledge cutoff
The knowledge cutoff is the date beyond which a language model has no more training data. For anything later, it must search the web (grounding) or risk answering with outdated or invented information.
Full definition →Knowledge Graph
Knowledge Graph
Knowledge base linking entities through typed relationships. Google’s powers the Knowledge Panel.
Full definition →L
Late chunking
Late chunking
Variant of chunking where the embedding is computed on the whole document before splitting, which preserves context.
Full definition →Listicle
Listicle
A listicle is content structured as a list of items, such as “the 10 best X tools”. Easy to scan and extract, it is heavily drawn on by AI engines, but being cited through a listicle does not guarantee being recommended.
Full definition →LLM (Large Language Model)
LLM
Language model trained on very large corpora, capable of generating text. ChatGPT, Gemini, Claude and Perplexity all rely on one or more LLMs.
Full definition →LLMO (Large Language Model Optimization)
LLMO
Another synonym of GEO, used mostly by tool vendors. Refers to optimizing content to be picked up by a large language model.
Full definition →LLM-readability
LLM-readability
How easily an LLM can parse, segment and extract content. Relies on explicit headings, standalone sections, stable terminology and high factual density.
Full definition →llms.txt
llms.txt
File proposed at a site’s root to steer LLMs toward relevant content. Unofficial standard, ignored by Google Search.
Full definition →Log file analysis
Log analysis
Analysis of server logs to observe the real behavior of bots. The only reliable way to check whether AI crawlers actually visit a site.
Full definition →M
Markdown
Markdown
Markdown is a lightweight markup text format (headings, lists, tables), readable by humans and easy for machines to parse. AI tools read it well and some sites serve Markdown versions of their pages, but Google states it is not useful for its search.
Full definition →MCP (Model Context Protocol)
Model Context Protocol
The Model Context Protocol (MCP) is an open standard for connecting AI applications to external systems: data, tools and workflows. It lets an assistant such as Claude or ChatGPT access information and perform tasks through standardized servers.
Full definition →Multimodal
Multimodal
A model’s ability to process text, image, audio and video together. Means treating visual content as an indexable asset, not decoration.
Full definition →N
NER (Named Entity Recognition)
NER
Automatic extraction of named entities from a text. Lets you audit what an engine actually identifies in a page.
Full definition →Non-commodity content
Non-commodity content
Non-commodity content is, according to Google, content that brings its own viewpoint or experience, beyond the common knowledge that any source or generative model could produce. Google puts this criterion first in its guide to generative AI features.
Full definition →O
Orphan page
Page orpheline
Page that receives no internal link. Hard for crawlers to discover and deprived of any authority signal.
Full definition →P
Parametric memory
Mémoire paramétrique
Knowledge encoded in a model’s weights during training, as opposed to information retrieved live from the web. It never produces a citation.
Full definition →Parasite SEO
Parasite SEO
Parasite SEO consists of publishing content on a high-authority third-party site to borrow its ranking and reach. Google treats abusive forms under its site reputation abuse policy, and platforms heavily cited by AI, such as Reddit, also feed its GEO version.
Full definition →Passage indexing (passage ranking)
Passage indexing
Indexing and ranking at the passage level rather than the whole page. Predates LLMs at Google, but central with generative retrieval.
Full definition →Pillar page
Page pilier
Reference page that covers a subject in depth and links to satellite pages. Natural candidate for citation by an AI engine.
Full definition →Prompt
Prompt
Instruction sent to an LLM. In GEO, the prompt is the equivalent of the keyword: the unit on which visibility is measured.
Full definition →Q
Query Fan-Out
Query Fan-Out
Technique by which an AI engine breaks a query into several sub-queries run in parallel, then synthesizes the results. A practitioner term; Google speaks of query variant generation (patent US11663201B2).
Full definition →Query rewriting
Query rewriting
Rephrasing of a user query by the engine before retrieval. The name ChatGPT uses for a mechanism close to query fan-out.
Full definition →R
Reciprocal Rank Fusion (RRF)
RRF
Method that merges the scores of several rankings into one. Used to aggregate the results of a query fan-out’s different sub-queries.
Full definition →Recommendation poisoning
Recommendation poisoning
Manipulation technique that injects content to skew an AI engine’s recommendations. Documented and confirmed by Microsoft.
Full definition →Relevance engineering
Relevance engineering
Relevance engineering is a discipline popularized by Mike King (iPullRank) that treats search visibility as an engineering problem: measuring a page’s relevance to a query, notably with embeddings and cosine similarity. It combines information retrieval, AI, content, UX and digital PR.
Full definition →Rendering
Rendering
Execution of JavaScript by the engine to obtain the final DOM. Client-side injected content can be invisible to bots without rendering.
Full definition →Reranking
Reranking
Reranking is a second ranking pass: after a first retrieval of candidates, a more precise model, often a cross-encoder, reorders the passages by their relevance to the query. It decides what actually reaches the model’s context.
Full definition →Retrieval-Augmented Generation (RAG)
RAG
Architecture combining document retrieval with a generative model: the system retrieves relevant passages, then generates an answer from them. The mechanism behind AI engine citations.
Full definition →robots.txt
Robots.txt
File at a site’s root telling bots which areas they may crawl. The main lever to allow or block AI crawlers.
Full definition →S
Salience
Salience
Score measuring the importance of an entity within a text, computed notably by Google’s Natural Language API. A target entity with low salience signals diluted content.
Full definition →Scaled content abuse
Scaled content abuse
Scaled content abuse is a violation of Google’s spam policies: producing many pages with no value for users, with the primary purpose of manipulating rankings. Google’s generative AI guide applies it to pages created for every query or fan-out variant.
Full definition →Schema.org
Schema.org
Standardized vocabulary for structured data, maintained by Google, Microsoft, Yahoo and Yandex. Version 30.0 was released in March 2026.
Full definition →Search Everywhere Optimization
Search Everywhere Optimization
Search Everywhere Optimization is a rereading of the SEO acronym: being visible wherever people search, including social networks, video platforms, marketplaces and AI engines, not just on Google. The term is promoted by practitioners and tool vendors, with no official definition.
Full definition →Search generative AI control
Search generative AI control
The Search generative AI control is the Search Console setting that lets a site owner include or exclude their content from Google Search’s generative AI features: AI Overviews, AI Mode and the AI features in Discover. It has been rolled out to all sites since August 31, 2026.
Full definition →Semantic cocoon
Cocon sémantique
Organization of a set of pages around a pillar page, linked by thematic internal linking. Covers more sub-queries than a single page on a broad subject.
Full definition →Semantic search
Semantic search
Semantic search seeks to understand the meaning and intent of a query rather than match exact words. It generally relies on embeddings and is the basis of modern AI engines.
Full definition →SEO migration
Migration SEO
Redesign, domain change or CMS change with a redirect plan and monitoring. A classic breaking point for visibility.
Full definition →SERP
Search Engine Results Page
The SERP (Search Engine Results Page) is the page an engine displays after a query. It now mixes classic links, snippets, maps, videos and AI summaries such as AI Overviews, and each element is worked differently.
Full definition →Server-Side Rendering (SSR)
SSR
HTML generation on the server before sending to the browser. Recommended for GEO: most LLM crawlers do not render JavaScript.
Full definition →SGE (Search Generative Experience)
SGE
Original name of AI Overviews during their 2023-2024 test phase. Obsolete since the rebranding, but still used out of habit.
Full definition →Share of Authority
Share of Authority
A brand’s share of authority in a topical field versus its competitors. A practitioner term with no standardized definition.
Full definition →Source type
Source type
Source type is the category of the domain cited or used by an AI engine: for example brand site, editorial media, reviews, social network or forum. GEO tracking tools use it to show where citations come from and where the brand needs to be present.
Full definition →Source visibility
Source visibility
Source visibility measures the share of AI answers where a site’s domain or content was used or cited, even if the brand is not named. It differs from brand visibility, which measures answers where the brand’s name appears explicitly.
Full definition →Structured data
Données structurées
Machine-readable markup describing a page’s content, preferably in JSON-LD. Helps entity understanding and rich results; Google requires no special markup for generative AI.
Full definition →Sub-query
Sous-requête
Synthetic query generated by an AI engine from the initial query. Google patent analyses identify eight recurring forms.
Full definition →T
Thin content
Thin content
Page with low added value, with no depth or original information. Rarely cited by AI engines.
Full definition →Token
Token
A token is the unit of text a language model processes: a word, part of a word, a character or a punctuation mark. The number of tokens, not words, determines what fits in the context window and what a call costs.
Full definition →Topical authority
Autorité topique
Recognition of a site as a reference on a subject, built through exhaustive, consistent coverage rather than isolated pages.
Full definition →TTFB (Time To First Byte)
TTFB
Delay between the request and the first byte received. A high TTFB penalizes crawling and AI crawlers’ access.
Full definition →U
Universal Commerce Protocol (UCP)
UCP
The Universal Commerce Protocol (UCP) is an emerging protocol cited by Google in its generative AI guide: it is meant to let search agents complete more commerce tasks on merchant sites. Google presents it as a standard that is still emerging.
Full definition →V
Vector search
Recherche vectorielle
Search by semantic closeness between embeddings, rather than keyword matching.
Full definition →W
WebMCP
WebMCP
Emerging standard that lets a site expose functions AI agents can use, beyond plain text content.
Full definition →Wikidata
Wikidata
Free, structured knowledge base. A major source of entity disambiguation for engines and LLMs.
Full definition →X
XML sitemap
Sitemap XML
File listing a site’s URLs to help discovery. Useful on large sites and to signal freshness.
Full definition →Z
Zero-click search
Zéro-clic
Search whose answer is provided directly in the SERP or AI interface, with no click to a site. AI Overviews and LLMs structurally amplify this.
Full definition →No term matches. Try an acronym (RAG, AIO, SGE) or a word from the definition.
Frequently asked questions about GEO vocabulary
What is the difference between GEO, AEO, LLMO and AI SEO?
No established difference of substance. GEO (Generative Engine Optimization), AEO (Answer Engine Optimization), LLMO (Large Language Model Optimization) and AI SEO all refer to the same practice: optimizing to be cited in AI-generated answers. No consensus definition separates them in academic literature in early 2026, and practitioners use them interchangeably. GEO is the most widespread term.
Does GEO replace SEO?
No. In 2026 Google published official documentation titled “Optimizing your website for generative AI features on Google Search”, in which it states that optimizing for generative search remains SEO. GEO adds requirements of structure and citability; it does not replace the technical fundamentals: crawling, indexing, rendering, authority.
Why must a definition fit in one sentence for GEO?
Because many AI engines do not read a page from top to bottom: they split it into chunks, score each passage independently, and cite the strongest ones. A standalone passage of 40 to 75 words that answers the heading’s question directly is mechanically more likely to be extracted than a paragraph that builds its reasoning before concluding. Google states, however, that no splitting is required for Google Search: the finding mainly applies to other engines and RAG systems.
Which GEO terms are really new, and which are renamed SEO?
Really new: query fan-out, grounding, chunking, embeddings, RAG, llms.txt, agentic commerce, AI share of voice. Renamed or extended SEO: E-E-A-T, entities, structured data, topical authority, internal linking. The second category is no less important; it simply predates generative AI.
How this glossary is built
Each term follows the same structure: English name, French equivalent, standalone definition in one or two sentences, category, and a link to a dedicated page. Definitions are dated and sourced on each term’s page. Terms whose usage is not settled in the industry are flagged as such rather than presented as established.