VisibleDiagnostic · Glossary

AI visibility glossary: the words that matter when measuring AI answers

Short, working definitions — written for marketers who have to explain the difference between being mentioned and being cited.

AI visibility

Whether an AI answer engine names a brand when a buyer asks a category question, and whether it points to the brand’s own pages as the source. It is measured separately from search rankings because the answer engine can name a brand without citing it.

AI answer engine

The assistant layer that returns a written answer instead of a list of links — for example ChatGPT, Perplexity, Gemini, Copilot. For marketing measurement the relevant output is the answer text, the named brands and the cited sources.

AEO (Answer Engine Optimization)

The work of making a brand likely to be named and cited in AI answers: publishing pages that answer real buyer questions, structuring the content so it can be quoted, and earning mentions on the pages the engine already trusts.

GEO (Generative Engine Optimization)

Overlaps with AEO; usually refers to optimizing for generative engines specifically (the multi-step retrieval-and-generation stack), including how sources are retrieved and how passages are quoted.

Mention

The AI answer names the brand in its text. A mention is what most “AI visibility” screenshots show. It does not mean the brand owns the evidence behind the claim.

Citation

The AI answer points to a page as the supporting source. Citation ownership is the harder and more durable metric: when the engine cites the brand’s own site, the brand controls the evidence.

Citation share

The share of answers for a question set where the brand’s own domain is cited, compared with three named competitors. Reported as a fraction, e.g. 1/3 answers.

Source audit

A list of the pages that won the citation for each buyer question, traced to host and page. It is the working document for content decisions: it shows which comparison pages, docs pages or review pages the engine trusts.

Pilot run

A single logged-out run of a question set, used as a sample. It is not a verdict: answers vary between sessions, which is why the paid diagnostic repeats each question three times across three days.

Use these definitions freely. If you quote them, please link back to this page. The pilot index they refer to: 17 brands, 51 answers · method.