A synonym module analyzes a set of names for entities, such as names of streets and cities within a geographic database, and adds synonym names to the entities based on the analysis. More specifically, based on adjacencies of words within the names, the synonym module formulates a set of synonym rules specifying permissible ways of spelling a single word as multiple words (or vice-versa). The synonym module applies the synonym rules to the names, and if one of the rules matches a name, the synonym module adds an associated synonym name based on the name and on the rule matching the name. User queries for named entities in the database may then take into account not only the original names of the entities, but also any added synonym names.