Definition
Query fan-out is the process where an AI engine expands one user question into multiple internal sub-queries, retrieves results for each, then synthesizes a single answer. Google's AI Mode publicly describes this technique. Fan-out means your page can be cited for a question it never targeted verbatim — the engine may pull you in via a sub-query about pricing, a definition or a comparison. The practical implication: a comparison page can be cited for a pricing sub-query, and a glossary definition can be pulled into a buying-guide answer. Structuring pages so each section answers one self-contained question — with its own heading, evidence and definition — turns a single URL into many fan-out targets, which is why section-level structure matters more in GEO than page-level keyword targeting did in classic SEO.