Do you mean tea which is what you have at tea time? Supper is what you have before going to bed and is usually cornflakes or maybe a couple of crackers (but tonight is a couple of Freddos).
Early dinner was a salmon fillet and a few huge prawns marinated in chipotle chilli paste plus garlic mayo. Later I had some egg mayo and an avocado. Also a bit of dark chocolate.
Lunch happens at lunchtime, supper is an informal evening meal, and dinner is more formal. If I ask friends to supper, they know they can turn up dressed casually and will get a one-plate meal and a few glasses of wine - probably served at the kitchen table rather than in the dining room. An invitation to dinner would mean dressing up a bit more and at least four courses eaten throughout the evening accompanied by copious servings of a variety of alcoholic beverages. Hic!