Systems and methods for semantic search are provided. A corpus of information grouped into passages are indexed by semantic key terms generated from packed knowledge representations that document the semantic relationships of information within those passages. When a search is conducted, a query is similarly transformed into a packed knowledge representation that documents the semantic relationships from which semantic key terms are also generated. An inverted index relating the semantic key terms associated to the passages is searched using the semantic key terms generated from the query. A set of candidate passages is selected and refined by analysis of the semantic key terms and other information. The semantic representations associated with the set of candidate passages are then matched to the semantic representation of the query to determine a search result set.