A property representing the relationship of the NCI Thesaurus (NCIt) concept to the term from the outside source. There are four possibilities: 1) Has Synonym: the two terms are synonymous; 2) Broader Than: the NCIt concept is broader than the mapped (target) term; 3) Narrower Than: the NCIt concept is narrower than the mapped (target) term; 4) Related To: the NCIt concept is somehow related to the mapped (target) term.