Grammar

1.16 Things which can be counted: count nouns

Many nouns have two forms, the singular form, which is used to refer to one person or thing, and the plural form, which is used to refer to more than one person or thing.

These nouns refer to people or things which can be counted. You can put numbers in front of them.

...book...books.
...day...days.
...three brothers.
...ten minutes.

These nouns make up the largest group of nouns in English. They are called count nouns or countable nouns.