9. A system comprising: one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising: receiving a query that includes a geographic entity name; identifying a different geographic entity name that is a candidate synonym of the geographic entity name; determining a relationship between the geographic entity name and the different geographic entity name in a geographic data set that includes a plurality of names of geographic entities and respective relationships between pairs of geographic entities; and determining not to revise the query based on the relationship between the geographic entity name and the different geographic entity name.
9. A system comprising: one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising: receiving a query that includes a geographic entity name; identifying a different geographic entity name that is a candidate synonym of the geographic entity name; determining a relationship between the geographic entity name and the different geographic entity name in a geographic data set that includes a plurality of names of geographic entities and respective relationships between pairs of geographic entities; and determining not to revise the query based on the relationship between the geographic entity name and the different geographic entity name. 10. The system of claim 9 , wherein the geographic data set is a tree structure wherein different positions in the tree structure that share a same level correspond to different geographic locations that share a same geographic region type.