In Britain this was, largely (she says putting her hands over her head and waiting for the fallout) a class issue.
At the time you were writing this, Jo, I was teaching it in Kirkby Lonsdale - in almost the same words!

The word "dinner" was used - in the C19 particularly, although before that as well - for the main meal of the day by all classes - what differed was when it was eaten!
The leisured classes ate dinner at about 4 or 5 pm in the early part of the C19, but that gradually got later in the evening as the century progressed - this is a lot to do with the availability of gas lighting, making preparation and washing up in the kitchen below stairs more practical.
The working classes tended to go home from the factory or workshop, or stop work on the hand-loom at home, in the middle of the day for their big meal (which was fairly small for the poorer classes in any case) In some cases, the eldest child not working would bring hot food to the factory gate for Dad. When he got home in the evening, he would have a much lighter meal known either as "tea" or "Supper" - depends a bit what part of the country and which end of the century you are examining.

Later in the century, when commuting to work over some distance was more common (suburban train services, horse-trams and omnibusses) a big meal at mid-day was no longer possible - the workman took his "baggins" (snap, pack-up, or what ever - different names in different regions) with him and had his main meal when he got home. But he still called it "Tea" or "Supper" - this is where the class connotations that persist even to the present day in this class-ridden country had their origin.

Class dismiss!
As the century progressed