Indefinite article, l’articolo indeterminativo
The indefinite article, (in English, “a” or “an”) is used to talk about non-specific persons, places or things. It is used when the noun has not been defined. E.g.,
un bicchiere = a glass/cup; una finestra = a window
The form of the indefinite article (un/uno/una/un’) will agree with the gender and number of the noun it is referring to.
Indefinite articles:
*Although rare, masculine nouns beginning with ps, gn, or y will function the same way.