Systems, methods, and other embodiments associated with logically expanding a document and determining the relevance of the logically expanded document to a query are described. One method embodiment includes searching an index to locate a document identifier for a document in which a query term appears. The method includes determining whether the index entry includes an expansion identifier, and, if so, producing a logically expanded document. The logically expanded document may include both a document associated with the document identifier and a document associated with the expansion identifier. The method may then determine a relevance value of the logically expanded document with respect to the query and may provide a signal corresponding to the relevance value.