In this paper, we describe the role and the use of WORDNET as an external lexical resource in a methodology for matching hierarchical classification schemas. The main difference between our methodology and others which were presented is that we pay a lot of effort in eliciting the meaning of the structures we match, and we do this by using extensively lexical knowledge about the words occurring in labels. The result of this elicitation process is encoded in a formal language, called WDL (WORDNET Description Logic), which is our proposal for injecting lexical semantics into more standard knowledge representation languages.