Noun

In linguistics, a noun or noun substantive is a lexical category which is defined in terms of how its members combine with other kinds of expressions. Since different languages have different inventories of kinds of expressions, the definition of noun will differ from language to language. In English, nouns may be defined as those words which can co-occur with definite articles and attributive adjectives, and function as the head of a noun phrase. The noun can be replaced by a pronoun of first person, second person, or even third person. Also the noun is known for being one of the eight parts of speech.

Expressions of natural language have properties at different levels. They have formal properties, like what kinds of morphological prefixes or suffixes they take and what kinds of other expressions they combine with; but they also have semantic properties, i.e. properties pertaining to their meaning. The definition of a noun at the outset of this page is thus a formal, traditional grammatical definition. That definition, for the most part, is considered uncontroversial and furnishes the propensity for certain language users to effectively distinguish most nouns from non-nouns. However, it has the disadvantage that it does not apply to nouns in all languages. For example in Russian, there are no definite articles, so one cannot define nouns as words that are modified by definite articles.

Classification of Nouns in English

Countable and uncountable nouns

Count nouns are common nouns that can take a plural, can combine with numerals or quantifiers (e.g. "one", "two", "several", "every", "most"), and can take an indefinite article ("a" or "an"). Examples of count nouns are "chair", "nose", and "occasion".

Mass nouns (or non-count nouns) differ from count nouns in precisely that respect: they can't take plural or combine with number words or quantifiers. Examples from English include "laughter", "cutlery", "helium", and "furniture". For example, it is not possible to refer to "a furniture" or "three furnitures". This is true even though the pieces of furniture comprising "furniture" could be counted. Thus the distinction between mass and count nouns shouldn't be made in terms of what sorts of things the nouns refer to, but rather in terms of how the nouns present these entities

Collective nouns

Collective nouns are nouns that refer to groups consisting of more than one individual or entity, even when they are inflected for the singular. Examples include "committee", "herd", and "school" (of herring). These nouns have slightly different grammatical properties than other nouns. For example, the noun phrases that they head can serve as the subject of a collective predicate, even when they are inflected for the singular. A collective predicate is a predicate that normally can't take a singular subject. An example of the latter is "talked to each other".

Good: The boys talked to each other.
Bad: *The boy talked to each other.
Good: The committee talked to each other.

Concrete nouns and abstract nouns

Concrete nouns refer to physical bodies which you use at least one of your senses to observe. For instance, "chair", "apple", or "Janet". Abstract nouns on the other hand refer to abstract objects, that is ideas or concepts, such as "justice" or "hate". While this distinction is sometimes useful, the boundary between the two of them is not always clear; consider, for example, the noun "art". In English, many abstract nouns are formed by adding noun-forming suffixes ("-ness", "-ity", "-tion") to adjectives or verbs. Examples are "happiness", "circulation" and "serenity".