If you find yourself ordering a pizza at most restaurants in Italy, don't expect to receive it already sliced. Typically, you'll receive a perfectly intact, unsliced pie. Some Italians argue that sliced food is meant primarily for a fast food context, not the more formal setting of a restaurant. However, this means that it's still possible to find sliced pizza in Italy if you go to the right place, although you won't exactly get a New York-style slice of pizza. Pizza al taglio refers to pizza that's made as a large square or rectangle and served as slices. It's typically cut in front of you with customers indicating the size of the slice they want, paying based on the weight of the slice.

Source: Chowhound