The nuns in Saskatchewan (mostly of German descent; I'm not sure if that's relevant) who taught me high school used to use the word "lunch" to describe what anyone else might understand as a "bedtime snack". Apparently that's the older meaning of lunch and for some reason it has stuck around in Saskatchewan.
In my own lexicon, the midday meal is lunch, the evening meal is supper, and dinner is either of these if it is substantial. It gets confusing in my house because my husband calls the evening meal dinner pretty consistently. There was one incident of honest confusion one Saturday when we discussed "dinner" for Sunday and he was startled the next day to see me making a big fuss in the kitchen at noon - he was expecting this meal in the evening! (In my family the noon meal on Sunday was always the elaborate one, so it didn't occur to me that he thought otherwise...)
