Pecorino Romano is a hard, salty Italian cheese, often used for grating, made with sheep's milk. The name "pecorino" simply means "ovine" or "of sheep" in Italian; the name of the cheese, although protected, is a simple description rather than a brand:  pecorino romano is simply "sheep's of Rome".
 
Pecorino Romano is most often used on pasta dishes, like the better-known Parmigiano Reggiano. Its distinctive aromatic and pleasantly sharp, very salty flavor led to it being preferred for some Italian pasta dishes with highly flavored sauces, especially those of Roman origin, such as bucatini all'amatriciana, spaghetti alla carbonara, and spaghetti cacio e pepe. The sharpness depends on the period of maturation, which varies from five months for a table cheese to eight months or longer for a grating cheese. 

Most pecorino cheeses are classified as grana and are granular, hard and sharply flavored.