@PotomacBobThe terms for meals is generally determined by era, nation/region (and the Urban/Rural divide), Class, and other factors.
Breakfast ("Breaking the Fast") might be a light meal, however, for those who typically performed hard physical labor outdoors, it was a substantial meal, if possible. Porridge/oatmeal/gruel, fortified with meat if possible; or Eggs, bacon/sausage (or beefsteak), potatoes, and perhaps fruit, toast, etc. Typically eaten shortly after Dawn (and pre-dawn chores in the early Spring, late Fall, and Winter).
Miday meal was Dinner, more so when the Sun determined the hours of the workday. It was the most substantial meal of the day, and typically the entire (extended) Family gathered together to eat it. {Breakfast might be eaten in shifts with some performing chores, and the womenfolk cooking, the menfolk ate, then the younger kids, and finally the womenfolk, while the older males were already out working.}
Lunch, as mentioned by others, became more common due to industrialization, and the impractabillity of men coming home for lunch (and mandatory schooling for children).
Tea was primarily for the "Leisure" Class(es), more-so the Gentry (and "Commerical") Class(es) than the Nobility. Ladies were most likely to do this daily (except on Sundays), and it was often social (on a small scale) an opportunity to pass on news and gossip, as well as plan upcoming events, etc.
The evening meal was Supper, as in soup (or stews, aka "Leftovers" from previous meals), and might be served cold (room temperature) rather than (re)heated. Supper was typically eaten near sundown, before or after, depending upon the time of the year. People usually went to bed soon after.
Dinner in the evening became more common as it became more common for men to work too far from home to eat a midday meal with family. Also, gaslight, and then electrical lighting, permitted people to remain awake longer after sundown.
Supper (has) remained more common in the Southern states of the USA, and the Plains (and other farming regions); as well as some parts of the United Kingdom and other parts of the English speaking world.