Locatelli is the brand name for a very high quality romano cheese. Romano is a grating cheese used alone or in combination with Parmesan. Romano cheese is very, very sharp. Locatelli romano is made from sheep's milk. Some people call it pecorino cheese which simply means sheep's milk cheese. Not all pecorino cheeses have the quality of Locatelli. In this case, there is really something to be said for the brand name.