Meal names aren't just regional, they're class related as well. And they can be affected by where you are. In schools, the room children eat lunch in is usually called the dinner room, so it gets called dinner by everyone, even if at home they have a strict lunch = midday, dinner = evening.
A roast dinner is always called that, even if eaten at lunch time. So my parents have a roast dinner for lunch.
High tea is an entree, followed by afternoon tea stuff such as sandwiches, cake etc. It's more of a northern thing, but my parents both had it at weekends in the boarding schools they went to, so we always had it on a Saturday. It's served around 5 - 6 pm, rather than 4 pm for afternoon tea.
Wisconsin still has supper clubs, so not just a Southern thing in the US.