It's a common additive in baked goods as well! I used to work at a bakery that would pump it through the HVAC to attract customers. People loved it, but all I could smell was vomit after being around it for so long. I rarely eat pastries anymore.
What's parm?
Parmesan cheese
Who calls Parmesan cheese "parm"? Is that a US thing?
Yes
On the east coast you'll also hear "pruhjhoot", "Muhtz" and "Sopresat" (prosciutto, mozzarella, soppressata).