The important thing to remember here is that dinner is considered by some to be the most important meal of the day. Supper, on the other hand, is something that is had only in the evening. And unlike dinner, it is usually a very light meal. One can have it early in the evening or just before going to bed. Americans tend to use the word supper quite often. It is usually a meal eaten at home with members of the family. When you invite someone to have a meal with you in the evening, you usually ask him/her to have dinner with you, not supper. The Prime Minister of India hosts dinners and not suppers.