Another common use of the genitive case is called the partitive genitive. This use shows something of which a part is taken. For example, in the phrase “a cup of sugar,” “sugar” would be in the genitive because it is the something of which a “cup” is taken.

Pars exercitū s extrā urbem manē bat. (Part of the army stayed outside the city.)

At times, what is partitive in English is not partitive in Latin and vice versa. In English you can say “all the people” or “all of the people” and it means the same thing. In Latin, you could say only omnēs hominē s. On the other hand, the Latin word nihil (nothing) uses a partitive genitive, so nihil cibī literally translates as “nothing of food,” meaning “no food.”