English divides nouns into count nouns and non-count nouns. Count nouns refer to things that can be counted as separate items. Non-count nouns refer to substances or concepts that are not divided into individual units. This distinction determines which words and forms are used to express quantity.

Word/Phrase	Definition
count noun	A noun that names items that can be counted as individual units.
non-count noun	A noun that names substances or concepts that are not counted as separate units.
quantity noun	A noun that refers to an amount or measurement, often used with non-count nouns.

Count nouns form the plural by adding -s or -es in regular patterns. Some nouns have irregular plurals that change the word form. Non-count nouns do not normally take a plural form in standard usage.

Rule
Most count nouns add -s for the plural.
Nouns ending in s, sh, ch, x, or z add -es for the plural.
Some nouns have irregular plural forms that must be memorized.
Non-count nouns do not take a plural in standard usage.

Some common English nouns form their plural with a vowel change or a different word. These plurals are used with the same rules as other count nouns once formed. They remain count nouns and take quantifiers like many or a few.

Subject	Form
child	children
person	people
man	men
woman	women
tooth	teeth
foot	feet

English uses different quantifiers with count nouns and non-count nouns. Many and few are used with plural count nouns. Much and little are used with non-count nouns. Some and a lot of can be used with both types, depending on context.

Word/Phrase	Definition
many	A quantifier used with plural count nouns to indicate a large number.
few	A quantifier used with plural count nouns to indicate a small number.
much	A quantifier used with non-count nouns to indicate a large amount.
little	A quantifier used with non-count nouns to indicate a small amount.

Singular count nouns usually require a determiner such as a, an, or the. Plural count nouns and non-count nouns can appear without a determiner when speaking generally. Specific reference often uses the with both plural and non-count nouns.

Rule
A singular count noun normally needs a determiner in a sentence.
The is used for specific nouns, both count and non-count.
Plural count nouns can be used without a determiner when speaking in general.
Non-count nouns can be used without a determiner when speaking in general.

Non-count nouns are often quantified by using measurement words or containers. These expressions create a unit that can be counted. The measurement word becomes a count noun and can take a plural.

Word/Phrase	Definition
a piece of	An expression that creates a countable unit from a non-count noun.
a cup of	A measurement that makes an amount countable as a unit.
a bottle of	A container that makes an amount countable as a unit.
a bit of	A small amount used with non-count nouns.

Counting nouns in English depends on the difference between count nouns and non-count nouns. Count nouns use plural forms and quantifiers like many, while non-count nouns use measurement expressions and quantifiers like much. Choosing the correct form and quantifier makes quantity clear and grammatical.