It was explained to me this way - all based on the time of day.
.
Elevensies 10-12
I thought that was invented by Tolkien for the Hobbits!

Growing up on the east coast of the US, we called it breakfast, lunch, and dinner or supper. But I don't really remember using the term supper since the 70s or 80s to me, I think it maybe fell out of fashion as a term?
Here in the north of England it's pretty much what TykeMan said:
The dinner at lunch time, and calling the evening meal tea is very much a northern thing.
When I was a kid
Breakfast
Dinner
Tea
Supper - usually cereal.
Dessert, if you have it, is directly after your main meal, it's pudding, sweet. It could be some strawberries and cream, ice cream, rice pudding etc.
But I still use the terms breakfast, lunch, dinner, dessert. Hubby says breakfast, lunch, tea, dessert.
Neither of us say pudding for dessert (though he probably did growing up), and I never use the term supper.
And I'm always way too stuffed to eat any snacks after dinner and dessert!