This is an abbreviation for SNOMED CT relationship.
An association between a source concept and a destination concept.
Each relationship is represented by a separate row in the relationship file.
Each relationship has a unique identifier and contains columns identifying the relationship type and the concepts that are related (sourceId "Reference term: sourceId (field)") and destinationId "Reference term: destinationId (field)")).
Each relationship provides defining information about the source concept.
Since July 2019, OWL axioms the authoritative representation of the stated view of concept definitions are represented by axioms distributed in OWL Expression Reference Sets. Relationships continue to be distributed to represent necessary normal form of the inferred view concept definitions.
The source, type and destination of one of the relationships for the concept are as follows:
Relationship
sourceId
typeId
destinationId
[ 74400008
appendicitis
](http://snomed.info/id/74400008 "74400008