Grammar

2.216 measurement nouns

Nouns referring to measurements are often used in partitive structures to refer to an amount of something which is a particular length, area, volume, or weight. Uncount nouns are used after 'of' in structures referring to length, and both uncount and plural nouns are used in structures referring to weight.

...ten yards of velvet.
Supar owns only five hundred square metres of land.
I drink a pint of milk a day.
...three pounds of strawberries.
...10 ounces of cheese.

Nouns referring to measurements are explained in paragraphs 2.267 to 2.274.