Meals please edit and add as appropriate
UK:
Breakfast - first meal of the day
Lunch (middle class) - eaten at midday (archaic/upper class: luncheon)
Dinner (working class) - eaten at midday
Tea (middle class) - light meal including the drink "tea" eaten in the late afternoon
Dinner (middle class) - cooked meal eaten in the evening
Supper (working class) - eaten in the evening
Supper (middle class) - snack/light meal eaten late evening
With the advent of the classless society this has all gone to pot, and in our house, for example, lunch refers to sandwiches or a light meal at midday, tea to similar in the evening, and dinner is a cooked meal eaten at midday or in the evening.
Canada:
Breakfast - first meal
Lunch - noon meal
Dinner - noon meal or evening meal - families call it differently
Supper - evening meal