King Size is Burger King, Supersize is McDonald's. (I haven't seen a "Well Endowed" Combo Meal yet, nor a "Heavy" Value Meal.)
After the movie "Supersize Me" came out, McDonald's "officially" quit using the term Supersize, but tonight, when I ordered a cheeseburger and Supersize fries, they still knew what I was talking about. Yum!