Parmesan (Italian: Parmigiano Reggiano, Italian: [parmiˈdʒaːno redˈdʒaːno]) is an Italian hard, granular cheese produced from cow's milk and aged at least 12 months or, outside the European Union, a locally produced imitation.
Parmigiano Reggiano is named after two of the areas which produce it, the Italian provinces of Parma and Reggio Emilia (Parmigiano is the Italian adjective for the city and province of Parma and Reggiano is the adjective for the province of Reggio Emilia); it is also produced in the part of Bologna west of the River Reno and in Modena (all of the above being located in the Emilia-Romagna region), as well as in the part of Mantua (Lombardy) on the south bank of the River Po.
The names Parmigiano Reggiano and Parmesan are protected designations of origin (PDO) for cheeses produced in these provinces under Italian and European law. Outside the EU, the name Parmesan is legally used for similar cheeses, with only the full Italian name unambiguously referring to PDO Parmigiano Reggiano.
It has been called the "king of cheeses" and "practically perfect food".