a midnight snack

To me this has a very specific meaning of having been in bed, then getting up needing "a little something" and eating in the kitchen in your pyjamas. If it's food in the late evening and I've been awake all day, I'll call it a "bedtime snack".

What I have concluded from this thread is that if any one of us were to invite anyone else over for a meal, the mealtime would probably have to be in UTC or something, to account for different time zones, and the meal itself would have to remain unnamed, so as not to cause confusion among dinners/supppers/lunches/teas. And as a result no one would quite know what type of food would be forthcoming!