Dinner, lunch, teatime, supper. What's the difference?

In the UK we have several meals, breakfast, lunch, dinner, tea, supper. Breakfast is obviously the first meal. But then it gets confusing.

Some call the mid day meal "Dinner" others call it "lunch."

Some call the early evening meal "Tea" which has nothing to do with the drink while others call it "Dinner"

For some "dinner" means a big meal regardless of time while "Lunch" is a light meal

Then there's "Supper" which is either a late night meal before bed or any evening meal and can mean "dinner" or "tea."

Personally I'd say lunch is a light mid day meal but dinner is a more substantial mid day meal. Teatime is between 5 to 8 while supper is anything after 9pm.

But what's your definition
Dinner, lunch, teatime, supper. What's the difference?
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