A concept object: contains the first concept (name, reference, id), the second concept(name, reference, id) and the relation between the 2 concepts The set of concepts (pair of concepts) 2 concepts and their relation ; value: the name of the searched concept. ID of the searched/first concept relation existing between the 2 concepts ID of the second concept name of the second concept The reference (name+ID) of the first concept The reference (name+ID) of the second concept The relation type existing between the two concepts A set of relation existing for the searched concept Defines the document as a toqe response instance The status (accepted, synonym) of the current concept