People use different names for meals.
Midday meal: dinner or lunch
The midday meal is called dinner by most people. This is especially common if it is the main meal of the day. Middle and upper class people usually call it lunch.
Some people usually have a light meal of tea and biscuits or cakes at four or five in the afternoon. This meal is usually called tea.
Early evening: high tea or supper
Many people have a cooked meal around five or six o’ clock. This is often called tea or high tea. Some people call it supper.
Later evening: supper or dinner
A meal later in the evening is often called supper. Some people use dinner for the evening meal if it is the main meal of the day.
Americans use lunch for the midday meal and dinner for the evening meals.