A plea for complex categories in ontologies

International audience; This paper investigates an issue at the interface between language and ontology. It is argued that the phenomenon of 'inherent polysemy' observed in lexical semantics for nouns such as book or country actually is a deeper phenomenon grounded on specific ontological relations involving the entities referred to. It is shown that this phenomenon emerges not only in language but also in most available ontologies. Beyond the 'dot types' used in some linguistic theories to account for logical polysemy, it is proposed to introduce 'complex categories' in ontologies in order to solve incoherence and inconsistency issues appearing when this phenomenon is not acknowledged and to characterize complex categories on the basis of formal ontology relations.