The definition and preparation of a Neapolitan ragù can vary from town to town, house to house, person to person. The Italian word ragù, from the French word ragout, is the basic term for a meat sauce in Italy. Ragù alla Bolognese, the most famous in America, is the tomato sauce made with chopped meat, where as a Ragù alla Napolitana is a tomato sauce in which large pieces of meat are slow cooked in the sauce for a couple of hours.
In the U.S., many of the early generations of Italian immigrants added more and more meat to the pot, including sausage, meatballs, braciola, and even pork chops and short ribs. In and around Naples, using only a stuffed, rolled meat, like a braciola (or involtini), is more common.
When to eat the meat is also a subject for discussion. In Italy, it is typical to first eat the pasta and sauce first, as a “primo,” and then have the meat course follow as a “secondo,” perhaps with a salad or vegetable. In the U.S, the salad may come first, and then the meat and pasta will typically be served at the same time.
Ironically, and cruelly, the trademark for the word ragù in the United States is owned by Unilever, which as far as I can tell, makes a jarred tomato-like sauce that has nothing to do with a real ragù!