A semantic/syntactic study of the Italian nominal system with special reference to the use of articles, including the use of the zero article in the non-determined noun phrase. The study takes as its point of departure the meaning of the subject-lexemes and the logico-semantic distinction between intension, i.e. the meaning of abstract concepts and features, and extension, i.e. the pointing out of entities in a world endowed with the indicated features. The author proposes a parallel distinction for the noun phrase, motivated by the fact that non-determined noun phrases in Italian normally only expresses the abstract concept of category, i.e. features by which entities may be categorised (eg: Ho bevuto vino; scrivo libri), whereas the determined syntagma actualises entities (Ho bevuto del vino/il vino; Ho scritto un libro/dei libri/i libri).