1. A system to generate a synonym dictionary, the system comprising: a processor; a receiving module that is executable by the processor that is operable to generate demand information based on a first plurality of queries; and a processing module that is executable by the processor that is operable to identify a second plurality of queries as a first cluster of queries from the first plurality of queries based on the demand information, the processing module to further identify a first synonym set based on an association map that comprises a first plurality of constraints identified from the second plurality of queries, the processing module to further store the first synonym set in a synonym dictionary.