AEO glossary: schema, entities, llms.txt, zero-click, citations and mentions

Use this glossary when a proposal, dashboard or technical conversation needs translating. The terms are grouped by what they help you understand: search, access, business identity and results. Each definition includes the business consequence. Some labels overlap; ask what work or measurement sits behind them before comparing suppliers.

Search and generated answers

AEO: answer engine optimisation

Work intended to help a business appear accurately in answers supplied by search and AI systems. It includes making information accessible, clear and supportable. AEO and GEO are used loosely and often interchangeably. Neither label specifies a fixed deliverable or gives an agency control over an engine's answer.

GEO: generative engine optimisation

A label for improving visibility in answers produced by generative AI. Some practitioners distinguish GEO from the broader AEO category, which can include extracted answers. Others mean the same work. Compare the actual research, technical changes, content and reporting, rather than buying a supposed distinction between the acronyms.

SEO: search engine optimisation

Work to improve a website's visibility in unpaid search results. It covers technical access, content and signals that help engines assess relevance. It overlaps with AEO because answers can draw on search results. Our AEO introduction explains that relationship without treating either discipline as a replacement for the other.

Answer engine

A system that responds to a question with an answer, rather than only a list of pages to visit. It may extract text, generate a response or combine approaches. For a business, the distinction matters because someone can learn about your services without opening your website.

LLM: large language model

A model trained on large amounts of data to process and generate language. An LLM is a component, not necessarily a search engine: a product can connect it to search tools. Publishing a page does not immediately change the model's training, even when a connected search tool can retrieve it.

AI Overviews

Google Search's generated summaries, with links to supporting web resources. They are a particular search feature, not a name for every AI answer. Inclusion is not guaranteed. Google's guidance explains eligibility; a supplier should distinguish this feature from other engines when reporting your visibility.

Prompt

The input given to an AI system, often a question or instruction. Wording and conversation context can change the response. For meaningful comparisons, record the questions used to test your business's visibility. A flattering answer to one carefully chosen prompt says little about other buyers' questions.

RAG: retrieval-augmented generation

An approach that retrieves relevant material and supplies it to a model to help generate an answer. The material might come from web search or a private document collection. Microsoft's explanation describes this pattern. Your page must first be found and selected to contribute through that retrieval process.

Grounding

Connecting a generated response to supplied information, such as retrieved documents, so its claims have a basis beyond the model's learned patterns. RAG is one way to provide that basis. Grounding does not certify truth: an outdated source can support an outdated answer about your prices or services.

Hallucination

A generated statement that is fabricated, incorrect or unsupported by the relevant evidence. It can sound confident and include a plausible reference. If an engine describes your business incorrectly, check the underlying sources before deciding what to fix. Accurate published facts help, but cannot guarantee accurate output.

Access and technical foundations

Crawlability

Whether an automated crawler can reach and fetch your pages. Access rules, server errors and broken links can obstruct it. Fetching a page is distinct from interpreting its content. Keep essential service details available in the delivered HTML so reading them does not depend on executing browser scripts.

Indexability

Whether a page is eligible to enter a search engine's index, its organised store of information used to serve results. Eligibility does not mean the engine has indexed it, ranked it or cited it. A technical report should distinguish those stages before claiming your business is visible.

robots.txt

A file that gives cooperating crawlers instructions about which paths they may fetch. It is not password protection, and blocking crawling is not a reliable way to remove a URL from search. Business owners need to know which crawler is being restricted and what access the rule affects.

llms.txt

A proposed convention for a Markdown file offering context and links to help AI agents use a website. The llms.txt proposal describes its purpose. Treat it as signposting: publishing one does not establish that a particular engine reads it, prefers your business or will cite you. It does not replace crawl controls.

Structured data

Information expressed in a machine-readable structure with named fields and relationships. On websites, this can explicitly describe an organisation, service or article. It should agree with the visible page. Marking a claim up makes it easier to interpret; it does not provide evidence that the claim is true.

Schema and JSON-LD

In website discussions, schema usually means the Schema.org vocabulary: agreed types and properties for describing things. JSON-LD is one format used to publish that description. They are different layers of structured data. Adding them cannot guarantee a citation, and choosing a service type does not prove expertise.

Business identity and credibility

Entity

A distinct thing, such as an organisation, person, place or product. Your trading name is text referring to an entity; it is not the entity itself. Clear names, addresses and relationships help distinguish your business from similarly named firms. Keep those facts consistent wherever you control their publication.

Knowledge graph

A representation of entities and their relationships, such as an organisation operating at a location or employing a person. Different systems maintain different graphs. Publishing structured facts does not guarantee entry in Google's or anyone else's graph. The practical job is to make your identity and relationships unambiguous.

Digital PR and backlinks

Digital PR seeks relevant coverage and references on other websites. A backlink is a link from another site to yours; coverage need not include one. An independent source can give readers evidence beyond your own claims. Neither a link nor an article automatically becomes an AI recommendation.

Visibility and commercial results

Citation

An attribution to a source, often shown as a link or numbered reference beside an answer. Inspect the destination and the claim it supports. Your page might be cited for a definition without your business being recommended. A visible reference also does not prove the source supports every surrounding sentence.

Mention

An appearance of your business or brand name in an answer. It may have no link, and the cited source may belong to someone else. Read the context: a neutral example, an explicit recommendation and a warning are all mentions, but have very different implications for a potential buyer.

Zero-click

A search interaction that ends without a click through to an external website. The user may have found enough information or abandoned the search. It is not inherently an AI event or evidence of satisfaction. Your business can appear in such an interaction without receiving a measurable website visit.

Share of voice

Your portion of visibility within a defined comparison set. AI reporting might count mentions or citations across selected prompts and competitors. Ask for the numerator, denominator, engines and testing dates. A share calculated from sampled answers is not your share of all buyer searches, demand or revenue.

Conversion and attribution

A conversion is a defined action, such as an enquiry or purchase. Attribution assigns credit for that action to touchpoints. Neither a citation nor a mention is automatically a conversion. Someone may discover you in an answer and return later, leaving incomplete evidence of what prompted the enquiry.