Two more school-related examples from Tuscany.

The Latin lapis for pencil instead of matita.

What do you erase the blackboard with? The correct Italian term is cimosa, but you'd hardly hear it outside Tuscany.

I'm also reminded of a discussion I once had with my grandma (a retired Latin teacher from Milan), when she heard someone say a word she claimed was dialect. As it turns out the word coccia comes from the Latin cochlea, which is a snail shell. Even after having taught Latin for 40 years, she didn't know the word...

Also seventh sky might not work in English, but seventh heaven works.