Abstract: The methods and systems of the invention involve the generation and use of a cross-linked keyphrase ontology database. The database is generated by defining at least one keyphrase, representing the keyphrase by a keyphrase node in an ontology, cross-linking the keyphrase node to a second keyphrase node, and then repeating the preceding steps for each keyphrase defined. A retrievable object can be indexed in a cross-linked keyphrase ontology database by representing the retrievable object by an object node in an ontology and then cross-linking the object node to a keyphrase node, where the keyphrase node represents a keyphrase in a second ontology and the keyphrase is related to the retrievable object. The cross-linked keyphrase ontology database can be searched by parsing a natural language statement into a structured representation and searching the cross-linked keyphrase ontology database. The cross-linked ontology database can be used for disambiguating syntactically ambiguous natural language statements.