Breakfast is in the morningAs a lower-middle class kid in Norfolk in the 60s, we were too posh to have tea as our evening meal but not posh enough to have dinner (I never heard that term till I went to London in 1980, everyone I knew had dinner in the middle of the day).
It was supper for us. But yeah, tea time was somewhere between 4pm and 5pm. Tea and cake for grown ups, orange squash for the kids.
Lunch is middle of the day
Tea is middle of the afternoon
Dinner is in the evening