SEO, AEO and GEO glossary: nine names, four real ideas

Core terms

• SEOearning visibility in search results. Google's 2026 guidance states that optimising for its generative features is still SEO.
• AEO (answer engine optimisation)optimising to be used and cited by assistants that answer instead of linking. See AEO.
• GEO (generative engine optimisation)optimising for AI summaries generated inside a search engine. See GEO.
• AI visibility: the rate at which a brand is cited, named or recommended inside AI answers, measured across a defined prompt set, platforms and dates.
• LLM visibility: a synonym for AI visibility. It describes the same outcome and we do not treat it as a separate discipline.
• Entity: a thing a machine can identify and hold facts about: a company, product, person or place. See entity optimisation.
• Citationan AI answer attributing a claim to a source. Distinct from a mention, which names a brand without attribution.
• Share of voiceyour presence relative to a named competitor set across a fixed prompt set. Meaningless without that competitor list.
• Groundingretrieving real sources to base an answer on, rather than answering from model knowledge alone.
• Non-determinism: the property that makes the same prompt return different answers on consecutive runs. The reason single readings are worthless.

Terms we are careful with

• llms.txt: a proposed file for describing a site to language models. Google states it receives no special treatment. Adoption sits under 10% of the top 1,000 websites. Useful to understand, not a service.
• AI visibility scoreany single blended number across platforms. Because platform overlap is low, a blended score hides the finding it should surface.
• Agentic searchdiscovery performed by autonomous agents rather than people. Real direction, immature category. We track it and do not sell it yet.