none of my friends really have a car yet, but I'm pretty sure I've heard it being called just the "car speaker", or "the car" (as in, "connect to the car"), mostly because i haven't seen people actually use the dashboard, and that because younger people don't carry music flash drives with them

Amazing. Like I understand "connect to the car," I get it, it's just wild to me to think of the car as just being a singular thing that has the feature of connecting to your phone rather than considering the device installed in the dash as being a separate thing with its own name.