Task

Query Expansion

Canonical ID https://id.searchplex.net/query-expansion/

Enriching a query with additional retrieval evidence intended to improve retrieval effectiveness.

Also called

Covers expansion of the query representation rather than ranking-stage relevance estimation.

Query Understanding Often implemented as a query-understanding workflow component.

Query Expansion is not Learned Sparse Retrieval. Learned sparse retrieval may produce expansion-like representations, but it is a retrieval representation family rather than the query-expansion task.
Query Expansion is not Query Understanding. Query understanding is the broader interpretation workflow; query expansion is one possible transformation within that workflow.
Query Expansion is not SPLADE. SPLADE is a learned sparse model family with expansion-like behavior, not the task of query expansion.