Lexicon · The human story of meaning
Relationship
Fully specified name: Relationship (concept)
A stated connection between entities or concepts.
- Scope note
- Record type and direction rather than an unlabeled connection.
- Synonyms
- None recorded as true synonyms in this context.
- Monograph
- Ontology (draft)
- External mappings
- None recorded. In W0 no mapping to SNOMED CT® or any external authority is asserted for this entry. A future mapping record will carry source system, identifier, version, relation type, evidence, author, confidence where meaningful, and review state.
- Formal status
- Editorial entry only. It is not part of any released ontology and a prose edit here changes no formal definition.
Draft. This entry is an unreviewed draft. Its sources have not been checked by a named person and no domain reviewer has approved it. Treat every claim as provisional.
Notes
A relationship is an assertion that connects two things and says how. The "how" is the relationship type: is a kind of, is part of, binds, is expressed in, was measured by. The direction says which way the assertion runs: a ligand binds a target, and the reverse statement, though often true, is a separate assertion that may need separate evidence. An unlabeled line between two nodes carries neither, and a system built from such lines can display connections but cannot answer a question.
The word is used across disciplines with different degrees of rigor. In a Taxonomy there is usually one relationship type, subsumption. In an Ontology written in a description logic, relationship types are themselves defined and may carry properties such as transitivity. In a Knowledge graph relationships are edges with labels, and the labels may or may not come from a controlled list. In clinical language, "related to" may mean anything from causation to co-occurrence. The NucLex rule is that a relationship record states its type from a named vocabulary, its direction, and the evidence behind it. An Interaction is a relationship with further structure: context, parameters, and uncertainty.