The meal in the evening is tea
Except that restaurants have dinner menus for the evening meal and lunch menus for the midday meal?
I'd love to see a restaurant with a 'tea' menu that wasn't pots of tea and cakes and small sandwiches, but the menu for the evening meal
Dinner is the main meal of the day regardless of when it is eaten
Hence a Sunday roast or Xmas meal that are during the day are Sunday dinner / Xmas dinner
Usually most people eat their main meal of the day in the evening. Hence why restaurants etc have dinner menus for the evening, and lunch menus for the daytime
Most people don't eat their main meal at midday. Hence why you don't pop out from work in the middle of the day to get 'a sandwich for dinner'.
Kids who have a hot meal during the day at school have school dinners served by dinner ladies
If they take sandwiches it's in a lunchbox, not a dinner box
Tea is a light early evening meal (5-6pm) that kids have if they're not old enough to eat dinner with their parents
Or for adults if you've had your main meal earlier
Morning meal - breakfast
Midday meal - lunch, unless it's the main meal of the day (in which case it's dinner)
Late afternoon / early evening (pre 6pm) - tea (for kids or adults as above)
Evening meal - dinner - unless you've had your main meal during the day. In which case if you have something light to eat during the evening it's either tea (early evening) or supper (late evening)
Clear as mud? 