Resource Description Framework (RDF)
Resource Description Framework, in short RDF, is a family of World Wide Web Consortium (W3C) specifications originally designed as a metadata data model. It has come to be used as a general method for conceptual description or modeling of information that is implemented in web resources, using a variety of syntax notations and data serialization formats.
RDF is based on the principle of object and subject and the relation between them. The relation is a predicate. Object, subject and predicate are RDF triples. SKOS, developed to express knowledge information systems such as controlled vocabularies and exchangeable in RDF, is completely built on triples.
Explore further the Linked Heritage learning object: Terminology.