Partitive Structure with Uncountable Nouns
To count or quantify an uncountable noun we use a unit of measurement - a measure word. For example, we cannot usually say “two breads” because “bread” is uncountable. So, if we want to specify a quantity of bread we use a measure word such as “loaf” or “slice” in a structure like “two loaves of bread” or “two slices of bread”. We call this structure a partitive structure.
We can use the same uncountable noun in different partitive expressions with different meanings. For example, a loaf of bread and a slice of bread are partitive expressions with different meanings. A loaf of bread is what we call a whole unit of bread that we buy from a baker. A slice of bread is what we call a smaller unit of bread after it has been cut from a loaf.
Here are some more examples:
The word "partitive" indicates that only "part" of a whole is being referred to. The partitive structure using a measure word is common with uncountable nouns, but it can also be used with countable nouns, for example: a series of accidents, two boxes of matches, a can of worms.
See also in Vocabulary: