It really depends where you live and when you eat.
Dinner was historically the main meal of the day, whether eating at lunchtime or in the evening. Nowadays dinner tends to refer the an evening meal.
Supper is often a lighter evening meal, and derives from the word soup.

You could easily eat all of the following throughout the day
Breakfast, brunch, lunch, afternoon/high tea, dinner, supper. With of course snacks in between