Abstract
The main claim of this work is that the traditional view whereby proper names are nothing but a subclass of common nouns is partially misleading. The paper therefore discusses some arguments in favour of a different classification of proper names within a multifaceted theory of lexicon, by examining relevant features such as semiotic status, syntactic behaviour (especially concerning their predicative function within nominal clauses), semantic properties (mostly building on the contrast between attributive vs. referential reading), as well as their phono-morphological shape and their interplay with other word classes. It finally argues that the singularities of proper names can be better understood if word classes are conceived as radically heterogeneous objects from a cognitive point of view, i.e. from the point of view of the way they are stored as natural, functional or scalar concepts in our mental lexicon.