Query Fan-Out
also: fan-out retrieval · query expansion
Expanding one query into many sub-queries issued in parallel, then merging the results.
Query fan-out rewrites a single request into several targeted sub-queries, runs them concurrently against the index or the web, and fuses the returned passages. It widens recall for complex questions — and it is how AI search engines dispatch one user prompt across many searches before synthesizing an answer.