(dinner, supper, tea, lunch)
In Britain, the main meal of the day is dinner and it is usually eaten in the evening. Some people call this meal supper, but to others supper is a very small meal that is eaten just before they go to bed. Some people call this main evening meal tea, but to others tea is a small meal that is eaten in the afternoon.
Some people use dinner to refer to the meal they eat in the middle of the day, but if you want to be clear that you are referring to this meal, use lunch.