countnoun

Count noun, also called a countable noun, is a noun that can denote discrete, individuated units and can be counted. Typical examples are apple, idea, and chair. This contrasts with mass nouns (or uncountable nouns) such as water, sand, and music, which typically do not have a discrete plural or are not counted directly without a unit of measurement.

Count nouns take the indefinite article a or an in the singular: a cat, an idea. In the plural or with numerals, determiners and numerals are used without the indefinite article: three cats, several ideas. Quantifiers such as many, few, a few, or a number of also apply to count nouns. The definite article the can refer to a specific count noun, as in the cats in the yard. Note that some English expressions use measure words for count nouns, e.g., three apples or two dollars.

Plural formation: Most count nouns form plurals by adding -s or -es. Irregular plurals include man/men, child/children, foot/feet. Some nouns have the same form in singular and plural (sheep, deer).

Context and nuance: Some nouns are context-dependent: "beer" can be mass when referring to liquid in general, but "beers" may refer to individual bottles. The distinction between count and non-count nouns is a feature of many languages, and some nouns change category depending on sense or usage. In linguistic descriptions, count nouns are contrasted with mass or uncountable nouns.