Partitive

In linguistics, the partitive is a word, phrase, or case that divides something into parts. For example, in the English sentence I'll have some coffee, some is a partitive determiner, because it makes the noun phrase some coffee refer to a subset of all coffee. Similarly, the preposition of often serves as a partitive, as in many of my friends, the youngest of the children, a glass of wine, some of the milk, and some of the people.