An  762676003 | OWL expression type reference set|  associates description logic statements with  SNOMED CT concept in the OWL functional syntax.

The SNOMED CT International Release contains content in two reference sets that follow the  762676003 | OWL expression type reference set|  pattern:

Data Structure

An  762676003 | OWL expression type reference set|  is structured as shown in the following table.


Data type


Part of Primary Key


A 128 bit unsigned Integer, uniquely identifying this reference set member.

Different versions of a reference set member share the same id but have different effectiveTime. This allows a reference set member to be modified or made inactive (i.e. removed from the active set) at a specified time.

NOYES (Full /Snapshot)

The inclusive date or time at which this version of the identified reference set member became the current version.

Note: In distribution files the effectiveTime should follow the short ISO date format (YYYYMMDD) and should not include the hours, minutes, seconds or timezone indicator.

The current version of this reference set member at time T is the version with the most recent effectiveTime prior to or equal to time T .


YES (Full)

Optional (Snapshot) 

The state of the identified reference set member as at the specified effectiveTime .

If active = 1 (true) the reference set member is part of the current version of the set, if active = 0 (false) the reference set member is not part of the current version of the set.


Identifies the SNOMED CT module that contains this reference set member as at the specified effectiveTime .

The value must be a subtype of 900000000000443000 | Module (core metadata concept)| within the metadata hierarchy.


Identifies the reference set to which this reference set member belongs.


A reference to the SNOMED CT component to be included in the reference set.

The concept to which the OWL expression applies. In the case of the 733073007 | OWL axiom reference set (foundation metadata concept)| , the axiom contributes to the definition of the identified concept.



The text of OWL expression to attach to the component identified by referencedComponentId.



The following metadata supports this reference set: 

     900000000000454005 |Foundation metadata concept|
900000000000455006 |Reference set|
762676003 |OWL expression type reference set|
762103008 |OWL ontology reference set|
733073007 |OWL axiom reference set|
900000000000457003 |Reference set attribute|
706999006 |Expression|
762677007 |OWL expression|
900000000000459000 |Attribute type|
900000000000465000 |String|
762678002 |OWL 2 language syntax|

Descriptor Template and Examples

The reference set example tables on this page have been revised as follows to aid clarity and understanding:

  • The first four columns which are present in all release files are not shown. The omitted columns ( id, effectiveTime, active) are used in the same way in all referenced sets to support identification, versioning and packaging. They do not directly affect the specific features of a particular reference set or reference set type.
  • Reference set columns that contain SNOMED CT identifiers are expanded to show details of the concept or description referenced by that identifier. In some cases, the term is shown in the same column using the expression syntax, in other cases an additional column with a name suffix '_term' has been added. In the standard reference set files only the identifier is present in the column and there is no added column for the term. When using reference sets, the term and other details of the component are looked up from the relevant component release files.

Descriptor Template

The table below shows the descriptors that define the structure of the  762676003 | OWL expression type reference set|  pattern and examples of the descriptors for specific reference sets that follow this pattern. 

Table 4-1: Descriptor templates for OWL expression reference rets

OWL Ontology Reference Set Example

Table 4-2: OWL ontology reference set example

OWL Axiom Reference Set Example

Table 4-3: OWL axiom reference set example


refsetIdreferencedComponentIdowlExpressionExplanatory Notes
SubClassOf(:404684003 :138875005)

Example of SubClassOf, which is equivalent to an | Is a| relationship between most SNOMED CT concepts.

A different OWL expression is used to represent | Is a| relationships between attributes. This is shown in the row below.

SubObjectPropertyOf(:774081006 :733928003)

Example of SubObjectPropertyOf, which is equivalent to an | Is a| relationship between attributes.

EquivalentClasses(:90708001 ObjectIntersectionOf(:64572001 ObjectSomeValuesFrom(:609096000 ObjectSomeValuesFrom(:363698007 :64033007))))

Example of EquivalentClasses. which is equivalent to stating that a concept is sufficiently defined by a set of necessary relationships.

EquivalentClasses(:126516008 ObjectIntersectionOf(:64572001 ObjectSomeValuesFrom(:609096000 ObjectIntersectionOf(ObjectSomeValuesFrom(:116676008 :108369006) ObjectSomeValuesFrom(:363698007 :371311000)))))

Example of a transitive object property.

SubObjectPropertyOf(ObjectPropertyChain(:127489000 :738774007) :127489000))
SubClassOf(ObjectIntersectionOf(:64859006 ObjectSomeValuesFrom(:609096000 ObjectSomeValuesFrom(:255234002 :387713003)) ObjectSomeValuesFrom(:609096000 ObjectSomeValuesFrom(:363698007 :272673000))) :703264005)

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