food economists that 'dinner' is the main meal of the day.  On Sundays or Holidays it is commonly served in the mid-day. But on any ordinary day most take their main meal in the early evening when the day is done and that is referred to as "supper" which would follow "lunch".  If the meal is a buffet style served in the evening it is always referred to as "supper" and not "dinner".

In the US it appears the terms “supper” and “dinner” are regional. I grew up in the Midwest using "dinner" and "supper" interchangeably as the evening meal or a special meal.  Others refer to the mid-day meal (what I'd call "lunch") as "dinner."  My friends in the Southern US insist that the only word to describe that evening meal is "supper."

We could also throw in the terms  “ tea”  or “brunch” but that would open a different can of worms.

 A  personal note from Aunt Milly:

 My husband and I go round and round on this.  If we ever get bored with discussion topics in our family - just  bring up this subject and we can get a lively discussion.  It seems to vary from how you were brought up in your area - so what do you call it? 

No matter what you call your meals, enjoy them and be thankful for the food and friends around the table.