Glossary

The AI search glossary

Plain definitions of the terms behind AI search: how assistants find, describe, and recommend brands, and what to do about it.

• AI Search Visibility

  AI search visibility is how often and how well AI assistants like ChatGPT, Claude, Perplexity, and Gemini name, describe, and recommend a brand when people ask. It measures whether you appear in AI answers at all, whether the description is accurate, and whether you are recommended over alternatives.

• Answer Engine Optimization (AEO)

  Answer Engine Optimization (AEO) is the practice of structuring your content and brand so that AI assistants like ChatGPT, Perplexity, and Google AI Overviews name you directly in their answers, not just link to you. Where classic SEO competes for ranked positions, AEO competes to be the answer itself.

• Generative Engine Optimization (GEO)

  Generative Engine Optimization (GEO) is the practice of structuring content so generative AI search, including Google AI Overviews, Perplexity, and ChatGPT search, can cite and synthesize it in answers. It focuses on clear claims, sources, and structure that make a page easy for a model to quote rather than rank.

• AI Overviews

  AI Overviews are Google's AI-generated answers that appear at the top of search results, above the traditional blue links. They summarize information from multiple web pages and show cited sources you can click. As of 2026, they often answer a question directly on the results page, which can reduce clicks to individual websites.

• llms.txt

  llms.txt is a proposed plain-text file placed at the root of a website, at /llms.txt, that gives large language models a curated Markdown summary of the site plus links to its most important pages. It is a voluntary, machine-readable hint, not an official standard, and adoption so far is limited.

• LLMO (Large Language Model Optimization)

  LLMO (Large Language Model Optimization) is the practice of making your content easy for large language models to understand, retrieve, and cite. It is largely interchangeable with AEO and GEO: all three describe getting a brand surfaced in AI-generated answers from tools like ChatGPT, Perplexity, Google AI Overviews, and Gemini.

• Zero-Click Search

  Zero-click search is when someone gets their answer directly on the results page, from an AI overview, a featured snippet, or a knowledge panel, without clicking through to any website. As of 2026 a large and growing share of searches end this way, which changes what visibility means: being named in the answer matters as much as ranking a link.

• Schema Markup (Structured Data)

  Schema markup is structured data you add to a web page, usually as Schema.org JSON-LD, that labels your facts (who you are, your products, hours, location, FAQs) so machines can read them unambiguously. It powers rich results in search and helps AI engines describe your brand accurately, though it never guarantees a citation.

• AI Crawlers

  AI crawlers are automated bots that AI companies use to read web pages for training and for live answers. Examples include OpenAI's GPTBot and OAI-SearchBot, PerplexityBot, Google-Extended, and ClaudeBot. If your robots.txt or firewall blocks them, you can be left out of AI answers, since an engine cannot cite a page it never fetched.

• Entity SEO

  Entity SEO is the practice of getting search engines and AI models to recognize your brand as a clear, consistent entity, a specific thing in the world with known attributes, rather than a loose set of keywords. It relies on consistent naming, accurate descriptions, and structured data so machines can connect every mention of you.