An ontology typically provides a vocabulary that describes a domain of interest and a specification of the meaning of terms used in the vocabulary. Depending on the precision of this specification, the notion of ontology encompasses several data/conceptual models, for example, classifications, database schemas, fully axiomatized theories. Ontologies tend to be put everywhere. They are viewed as the silver bullet for many applications, such as information integration, peer-to-peer systems, electronic commerce, semantic web services, social networks, and so on. They, indeed, are a practical means to conceptualize what is expressed in a computer format. However, in open or evolving systems, such as the semantic web, different parties would, in general, adopt different ontologies. Thus, just using ontologies, like just using XML, does not reduce heterogeneity: it raises heterogeneity problems at a higher level.

This web site provides a repository of information devoted to different aspects of ontology matching. Ontology matching is a promising solution to the semantic heterogeneity problem. It finds correspondences between semantically related entities of the ontologies. These correspondences can be used for various tasks, such as ontology merging, query answering, data translation, or for navigation on the semantic web. Thus, matching ontologies enables the knowledge and data expressed in the matched ontologies to interoperate.

We appreciate support from the KnowledgeWeb FP6 Network of Excellence which helped to form a basis for the creation of the Ontology Matching information resource.