1. A method of indexing entities, located in a taxonomy, said method comprising: retrieving said entities from documents, each of said entities being indexed by an entity alias and belonging to a group located by said taxonomy and indexed by a group name; building posting lists for all occurrences of each of said entities, each said posting list of the posting lists for all occurrences of said entities comprising a first data field, including a location in said documents for an occurrence of an entity of said entities, and a second data field, including a set of terms and data corresponding to said occurrence of said entity; building a posting list for said group of said all occurrences of each of said entities, said posting list for said group comprising a first data field, including a location in said documents for an occurrence of an entity of said entities, and a second data field comprising an entity alias corresponding to said occurrence for said entity; indexing, by said group name, said posting list for said group; and outputting said posting list for said group in response to a query using said group name.