GEO glossary
Short, plain definitions of the terms used in GEO and AI search.
- A
AEO
AEO (Answer Engine Optimization) is the practice of structuring content so that systems which answer users directly, such as featured snippets, voice assistants and AI chatbots, can use it as a short, clear answer to a specific question.
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AI crawlers
AI crawlers are bots that companies such as OpenAI, Anthropic, Perplexity and Google use to visit websites, whether to collect training data for models, find sources for AI search, or fetch a page at a user's request.
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AI Overviews
AI Overviews are short AI-generated summaries that Google shows above the regular results for some searches, produced with a Gemini model from several web sources and linking back to the pages they draw on.
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Citation rate
Citation rate is a metric used to measure AI visibility: the percentage of answers that AI assistants give to a fixed set of questions in which a given website or brand is cited as a source.
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E-E-A-T
E-E-A-T stands for Experience, Expertise, Authoritativeness and Trustworthiness, the concepts Google's Search Quality Rater Guidelines use to describe how reliable a piece of content and its creator are.
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Entity
An entity is a distinct person, organization, place, product or concept that search engines and AI systems can identify on its own and tell apart from others, defined by its attributes and its relationships with other entities.
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GEO
GEO (Generative Engine Optimization) is the set of content and technical practices that help a brand get mentioned accurately and cited as a source in answers generated by AI systems such as ChatGPT, Gemini, Perplexity and Google AI Overviews.
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Hallucination
A hallucination is when a large language model produces information that is wrong, unsupported by its sources or entirely made up, while presenting it in fluent, confident language as if it were true.
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IndexNow
IndexNow is an open protocol, announced by Microsoft Bing and Yandex in 2021, that lets a website notify participating search engines instantly, with a single request, when pages are added, updated or deleted.
- K
Knowledge graph
A knowledge graph is a data structure that stores entities such as people, organizations, places and concepts, along with the relationships between them, as a connected network; Google's Knowledge Graph, introduced in 2012, is the best-known example.
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Large language model (LLM)
A large language model (LLM) is an AI model trained on vast amounts of text to predict the next word in a sequence, which lets it answer questions, summarize documents, write and hold conversations.
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LLMO
LLMO (Large Language Model Optimization) is a term close in meaning to GEO, describing work that helps a brand appear accurately and visibly in answers produced by large language models such as ChatGPT, Claude and Gemini.
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llms.txt
llms.txt is a Markdown file placed at a website's root that briefly tells large language models what the site is about and which pages matter most; it was proposed in 2024 and is not yet an official standard.
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RAG
RAG (Retrieval-Augmented Generation) is a technique in which a large language model first retrieves content relevant to a question from a search engine, database or document collection, then bases its answer on that retrieved content.
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robots.txt
robots.txt is a plain-text file at the root of a website, based on the Robots Exclusion Protocol, that tells search engine and AI crawlers which parts of the site they may crawl and which they should leave alone.
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SEO
SEO (Search Engine Optimization) is the combination of technical, content and link-building work that helps a website rank higher in the free, organic results of search engines such as Google and Bing for relevant searches.
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Share of voice
Share of voice is the number of times a brand is mentioned in AI answers to a fixed set of questions, divided by the total mentions of all competing brands in those same answers, showing where it stands against competitors.
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Structured data
Structured data is information on a page, such as a business, person, product, article or FAQ, marked up with the schema.org vocabulary, usually in JSON-LD, so that search engines and other software can read it directly.
- Z
Zero-click
A zero-click search is one where the user gets the information they need directly from the results page, via a snippet, knowledge panel, AI summary or AI assistant, and ends the search without clicking through to any website.