OWL

OWL is the Web Ontology Language

Some excellent resources for information about and/or tools for OWL are:

• Co-ode - see in particular their tutorials
• The open source Pellet reasoner and OwlSight ontology browser supported by Clark and Parsia
• Manchester University's OWL resources
• TopBraid Composer, a commercial ontology editor from TopQuadrant
• Uli Sattler's list of description logic reasoners
• The Protege project. Both the open source version 3 and version 4 support OWL.

Note, Science Commons's own Alan Ruttenberg is one the chairs of the working group specifying the new OWL 2.