Morphological criteria:
- the noun carries the termination mark of Gender (amico/amica)
and number (amico/amici);
Syntactic criteria:
- the noun combines with other PoS' (det/adj) giving rise to Noun
Phrases of which the noun constitutes, in general,
the head. The head regulates the agreement
mechanism: Il mio caro amico parte/ I miei cari amici partono.
``Presentational"/graphical criteria:
- Proper Nouns are capitalized: Mario, Rossi, i Borboni, le Alpi. It should be noted that all capitalized nouns are not proper nouns: hence, this criterion is necessary but not sufficient.