At our house we have used both tea and dinner to refer to our evening meal.
When I was little we had our main meal at Lunch time and for our evening meal we would say tea (we would normaly have a light snack like sandwich etc). Then we started taking packed lunches to school with sandwiches and had our main meal in the evening so we started saying dinner!!!
We normally use either pudding or afters for desert!!

If someone comes round for our evening meal we say "they are coming to tea" too lol
Being invited round for tea can also mean afternoon tea
Ok question: why in America do you reply "this is she/he" instead of "speaking" if someones calls you and asks if it's you?