Growing up we called it supper at home, which was (and still is in my parents' home) at 6 p.m. Mom believed it was dinner if it was earlier in the day; when you had the major meal in the afternoon. So it would then be breakfast, dinner, and supper. Supper would then be a bowl of soup or something like that, dinner, at noon or early afternoon, would be the meat-and-potatoes big meal. At holidays we would eat (and I still do this to a degree) at around 3 p.m., and then it is dinner. Everyone has leftovers (turkey, ham sandwiches) around 7; that is supper. Now almost everyone I know uses the two words interchangeably, as do I.