The two SchemaOrg types DefinedTerm and DefinedTermSet are allowed in many places as property values.
In e.g. the life-sciences, there are a number of controlled vocabularies and ontologies, which are often used as source of the DefinedTerms. Many of the, can be browsed and accessed through terminology and lookup services or portals.
For linked data applications it is sufficient for an entity
with @type="DefinedTerm" to link to an @id pointing to the IRI
of the referenced concept.
In other cases, more information is needed to search and view defined term information
without having to lookup external resources. E.g., a domain-specific search engine
can create faceted search based on the name property, like e.g. done in TeSS.
Aforementioned terminology services also offer linking and query interfaces
beyond IRIs as parameters.
Another possible use of a conformant DefinedTerm
is to enable creating hyperlinks to other web ressources, e.g.
https://bio.tools/t?inputDataFormatID=%22format_3244%22
or provide tool-tips if the description is provided.
Some typical OBO ontologies can be taken as inspiration of properties that should be
required or recommended in a Bioschema DefinedTerm profile. We also provide
some mapping information between properties of DefinedTerm
and those from OBO, OWL and SKOS, following work in https://doi.org/10.1186/2041-1480-2-S1-S3.
It is not intended to duplicate the content and expressivity of powerful ontology representations and serialisations like OWL or RDF.