AEO and SEO glossary

An AI citation is a link or named reference to a web page that an AI answer engine shows as a source for its answer. It is the AI-search equivalent of a ranking: the page was used, and the reader can click through to it.

An AI crawler is a bot that AI companies use to fetch web pages, and its user agent is the name it identifies itself by in requests and in robots.txt rules. Providers typically run separate agents for model training, search indexing and fetching a page when a user asks.

AI Overviews are AI-generated summaries that Google shows at the top of some search results, with links to the web pages used to build the summary. They appear for certain queries only, alongside the normal list of results.

An answer engine is a search tool that responds to a question with a written answer rather than a list of links. ChatGPT with search, Perplexity, Google's AI Overviews, Gemini, Microsoft Copilot and Claude with web search all work as answer engines.

Answer engine optimisation (AEO) is the practice of making your content easy for AI answer engines to find, understand and cite when people ask questions your business can answer. It builds on SEO rather than replacing it.

Content decay is the gradual decline in a page's search impressions, rankings or clicks over time, usually because the page has become outdated, competitors have published better answers, or the search results themselves have changed.

A content gap is a question, topic or search your audience cares about that your website doesn't answer well, or at all. Content gap analysis finds those missing or weak answers so you can create or improve the right pages.

Entity consistency means your business is described the same way everywhere online: the same name, what you do, where you operate, contact details and key facts. It helps search engines and AI systems confidently recognise that different mentions refer to the same business.

Generative engine optimisation (GEO) is the work of improving how often and how accurately your brand and content appear in answers written by generative AI systems. In everyday use it overlaps almost entirely with answer engine optimisation.

Grounding is when an AI model bases its answer on information retrieved at the time of the question, such as live search results or documents, rather than only on what it learned in training. Grounded answers are usually the ones that show source links.

Keyword cannibalisation happens when two or more pages on the same site target the same search intent, so they compete with each other and search engines struggle to choose which one to show. It often results in neither page performing as well as one strong page would.

llms.txt is a proposed standard for a plain-text Markdown file at the root of a website (yoursite.com/llms.txt) that gives AI tools a concise summary of the site and links to its most useful pages. It is a proposal, not an official standard adopted by the major answer engines.

A near-win keyword is a search query where your page already ranks close to the top results, typically just off page one (around positions 8 to 25), so a focused improvement could move it to where it earns meaningful clicks.

Query fan-out is when an AI search system breaks one question into several related sub-queries, searches for each, and combines the results into a single answer. Google has described using this technique in its AI search features.

Topical authority is the idea that a site which covers a subject thoroughly, accurately and consistently becomes a more trusted source on that subject than a site with a single page about it. It is a useful concept rather than a single metric that search engines publish.

A zero-click search is a search where the person gets what they need on the results page or in an AI answer and doesn't click through to any website. Featured snippets, knowledge panels, AI Overviews and assistant answers all contribute to it.