"An ontology formally defines a common set of terms that are used to describe and represent a domain." - World Wide Web Consortium

• ANSI Ad Hoc Group on Ontology Standards
• Ontology-Based Metadata
• OWL Web Ontology Language - a revision of the DAML+OIL web ontology language, which facilitates greater machine readability of web content than XML, RDF, and RDF-S support by providing a additional vocabulary for term descriptions
• Feature Synopsis for OWL Lite and OWL - (W3C Working Draft as of 2002-08-07) provides an introduction to the OWL language
• OWL Web Ontology Language 1.0 Abstract Syntax - (W3C Working Draft as of 2002-08-07) high-level, abstract syntax for both OWL and OWL Lite, and a mapping from the abstract syntax to the OWL exchange syntax
• OWL Web Ontology Language 1.0 Reference - (W3C Working Draft as of 2002-08-07)
• Requirements for a Web Ontology Language - (W3C Working Draft as of 2002-07-19) specifies usage scenarios, goals and requirements for a web ontology language
• University of Michigan Digital Library (UMDL) Ontology: Concept Descriptions