RDF Schema (RDFS) is an extension to RDF.
RDF describes resources with classes, properties, and values.
In addition, RDF also needs a way to define application-specific classes and properties. Application-specific classes and properties must be defined using extensions to RDF.
One such extension is RDF Schema.
RDF Schema does not provide actual application-specific classes and properties.
Instead RDF Schema provides the framework to describe application-specific classes and properties.
Classes in RDF Schema are much like classes in object oriented programming languages. This allows resources to be defined as instances of classes, and subclasses of classes.
The following example demonstrates some of the RDFS facilities:
In the example above, the resource "horse" is a subclass of the class "animal".
Since an RDFS class is an RDF resource we can abbreviate the example above by using rdfs:Class instead of rdf:Description, and drop the rdf:type information: