835935 Ok, I can see that. Also on a possibly related note: over here in rural areas people used to eat their main meal during lunch time. But in major towns/cities that was at dinner/supper time.
Lunch is always middle of the day. Dinner and supper have varied use, as has been noted, but often supper implies something later and lighter. You can have a big dinner but not so much a big supper. At dinner you dine, at supper you merely sup.
"Dinner" has always been an evening meal in my circles, except at school where school lunches were served by dinner ladies.