1. A computer-implemented method, comprising: receiving a query term and a possible synonym for the query term; accessing a geographic data set that associates geographic location names with corresponding positions in 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; identifying a first position in the tree structure of the query term and identifying a second position in the tree structure of the possible synonym for the query term; determining that the query term and the possible synonym for the query term are problem synonyms based at least on a relative position of the first position in the tree structure with respect to the second position in the tree structure wherein the problem synonyms are two terms that have related geographic contexts according to the tree structure; and notifying a search engine that the query term and the possible synonym for the query term are problem synonyms.