These generative engine optimization terms come up once you move from measuring visibility to fixing it.
How GEO differs from SEO
GEO differs from SEO in how success is judged, while both rest on crawlable pages with clear answers. SEO is judged by rank in a results list. GEO is judged by whether the answer names your brand. The full comparison is in GEO vs SEO.
llms.txt
llms.txt is a Markdown file at a site's root that summarizes the site for AI agents and links to its key pages. It is still a proposal at llmstxt.org, not a standard every engine reads. See the llms.txt guide for setup.
Structured data
Structured data is markup that labels facts on a page, such as a product's price or an article's author. Most sites use the schema.org vocabulary, usually written as JSON-LD.
Chunking
Chunking is splitting a page into passages so a retrieval system can match each passage to a question. A section that stands on its own survives chunking better than one that leans on earlier paragraphs.
Query fan-out
Query fan-out is an engine issuing several related searches across subtopics to build one answer. Google says both AI Overviews and AI Mode may use this technique.