A representation of the internet
(Credit: Bill Cheswick, Lumeta Corp.)

In both computer science and information science, an ontology is a data model that represents a domain and is used to reason about the objects in that domain and the relations between them. Ontologies are used in artificial intelligence, the semantic web, software engineering and information architecture as a form of knowledge representation about the world or some part of it.

The term ontology has its origin in philosophy, where it is the name of a fundamental branch of metaphysics concerned with existence. According to Tom Gruber at Stanford University, the meaning of ontology in the context of computer science, however, is “a description of the concepts and relationships that can exist for an agent or a community of agents.” He goes on to specify that an ontology is generally written, “as a set of definitions of formal vocabulary.”

Swoogle is a search engine for the Semantic Web on the Web. Swoogle crawl the World Wide Web for a special class of web documents called Semantic Web documents, which are written in RDF (Resource Description Framework). Swoogle is a research project being carried out by the ebiquity research group in the Computer Science and Electrical Engineering Department at the University of Maryland, Baltimore County (UMBC).