The relationship between ontologies and natural language lexicons is a hotly debated one. An ontology is a formalized system of concepts (potentially of a specific domain) and the relations these concepts entertain. A lexicon, on the other hand, is the language component that contains the conventionalized knowledge of natural language speakers about lexical items (mostly words, but also morphemes and idioms). Ontologies ‘operate’ on the conceptual level, lexicons on the linguistic level. Ontologies systematize and relate concepts, lexicons systematize and relate words and other lexical items. However, as semantic relations between lexical items reflect meaning relatedness and meaning is essentially conceptual, both notions appear to be very close to one another (and are often wrongly used interchangeably). The interplay of and mapping between ontologies and lexical resources is therefore a vital and challenging field of research, one which has gained additional momentum and importance...