What is the difference between RDF Schema and Ontology?

Question

I am new to Semantic Web and confused regarding RDFs and Ontology. Can someone explain the difference between RDF Schema and Ontology?

Answer 1

As per the spec, RDF schema is purely that - a schema or structure for defining things semantically. It gives you the vocabulary (key words and properties) for describing things. Think of it like an XML schema as used in XML documents and web pages.

An ontology is a classification hierarchy (for example, the biological taxonomy of life) normally combined with instances of those classes. It is used for classifying and reasoning.

What is an instance depends on how you define a taxonomy. It might be that you have an ontology of living creatures and so a living, breathing person is an instance of the ontological class "Homo Sapiens", or it might be that you have an ontology of species and so the entire Homo Sapiens species is an instance of the ontological class "Species".