Supper vs Dinner

I just looked up the definition of supper on Wikipedia. It's funny how many different definitions there are since in most places in North America both terms have no difference. However, reading the wikipedia entry opens up a can of worms since different regions have different definitions. A couple of places call lunch as "dinner" and 'supper' for dinner. Another grouping uses dinner as a major evening meal and supper as a light evening meal.