For years my wife and I have argued about Dinner vs Supper. Believe it or not depending on which part of the country you are in saying dinner can actually mean lunch. My wife thought I was just stupid for years when I would argue with her that I had heard people use dinner to mean lunch. I searched the Internet over for proof that I wasn't crazy and finally found something.
Standard Version
Southern Version
The word "supper" typically means the last mean of the day but for whatever reason it isn't used much outside of the South. I lived in Michigan for eight years and cannot recall a single time I ever heard someone say supper. The word "dinner" means the main meal of the day. Obviously this is more vague and since you are not suppose to eat a heavy meal before going to bed I think this is why people have adopted saying dinner to also mean lunch. Dinner is usually eaten in the evening, but it can be eaten at lunchtime.
To fix the world's confusion I think this is what we should do.
My Version
This solves the problem of even using the word dinner and avoids confusion since supper is the last meal of the day. Logical, easy, no confusion.