I want to make normal sandwich bread. What's the yeast called in an Italian supermarket?
Apparently you're a foreigner living in Italy¹ and what you got was sour dough but if you want something that you're used to already you should get:


"Lievito di birra2 secco" if you want dry yeast
"Lievito di birra" if you want the real stuff that you have to keep in the fridge. 



Note¹: If you fill in a bit more about yourself in your user profile, we'll have to assume less.
Note²: Yes,  "Beer yeast"...  don't worry: It's a cultural thing...