Italian course A2, Italian indefinite article, when does one apostrophize and when not? a hero ...
There are 3 singular indefinite articles:
1) One is used for masculine singular nouns starting with:
s + consonant (a rock, a mirror, a fool)
pn (a tire) ps (a psychopath) or pt (a pterodactyl)
x (a xenophobe) y (a yogurt) or z (a backpack)
gn (a gnome)
i semiconsonantics (one ion)
2) A is used for masculine singular nouns in all other cases:
A dream, a ball, a day, an animal ..
3) Una is used for feminine singular nouns:
A beach, a girl, an anchor