Introduction

The number of applications where WordNet is being used as an ontology rather than as a mere lexical resource seems to be ever growing. However, WordNet is only really serviceable as an ontology if some of its lexical links are interpreted according to a referential semantics that tells us something about (our conceptualization of) ‘the world’. One such link is the hyponym/hypernym relation, which corresponds in many cases to the usual subsumption is-a relation between concepts. An early attempt at exploring the semantic and ontological problems lying behind this correspondence is described in Guarino, 1998b.

In recent years, we have developed a methodology for testing the ontological adequacy of taxonomic links called OntoClean (Guarino and Welty, 2002a, 2002b), which was used as a tool for a first systematic analysis of WordNet's upper-level taxonomy of nouns (Gangemi et al., 2001). OntoClean is based on an ontology of properties (unary universals), characterized by means of metaproperties. We complemented OntoClean with an ontology of particulars called DOLCE (Descriptive Ontology for Linguistic and Cognitive Engineering), which is presented here in some detail, although in an informal way. This ontology plays the role of a first reference module within a minimal library of foundational ontologies that we developed within the WonderWeb project.

This chapter is structured as follows. We discuss in the next section some ontological inadequacies of WordNet's taxonomy of nouns. Then we introduce the basic assumptions and distinctions underlying DOLCE, and discuss the preliminary results of an alignment work aimed at improving WordNet's overall ontological (and cognitive) adequacy, and facilitate its effective deployment in practical applications.