A noun (Latin: nōmen, "name")[1] is a word that functions as the name of some specific thing or set of things, such as living creatures, objects, places, actions, qualities, states of existence, or ideas.[2][note 1] Linguistically, a noun is a member of a large, open part of speech whose members can occur as the main word in the subjectof a clause, the object of a verb, or the object of a preposition.[3]

Lexical categories (parts of speech) are defined in terms of the ways in which their members combine with other kinds of expressions. The syntactic rules for nouns differ from language to language. In English, nouns are those words which can occur with articles and attributive adjectives and can function as the head of a noun phrase.

• 1 History
• 2 Definitions of nouns
• 3 Gender
• 4 Classification of nouns
  • 4.1 Proper nouns and common nouns
  • 4.2 Countable and uncountable nouns
  • 4.3 Collective nouns
  • 4.4 Concrete nouns and abstract nouns
• 5 Noun phrases
• 6 Pronouns
• 7 Nominalization
• 8 See also
• 9 Notes
• 10 References
• 11 Further reading
• 12 External links

Word classes (parts of speech) were described by Sanskrit grammarians from at least the 5th century BC. In Yāska's Nirukta, the noun (nāma) is one of the four main categories of words defined.[4]

The Ancient Greek equivalent was ónoma (ὄνομα), referred to by Plato in the Cratylus dialog, and later listed as one of the eight parts of speech in The Art of Grammar, attributed to Dionysius Thrax (2nd century BC). The term used in Latin grammar was nōmen. All of these terms for "noun" were also words meaning "name".[5] The English word noun is derived from the Latin term, through the Anglo-Norman noun.

The word classes were defined partly by the grammatical forms that they take. In Sanskrit, Greek and Latin, for example, nouns are categorized by gender and inflected for caseand number. Because adjectives share these three grammatical categories, adjectives were originally placed in the same class as nouns. For example, in The Art of Grammar, words of adjectival type are largely contained in the subclass of ónoma described as paragōgón (plural paragōgá),[6] meaning "derived".[7] Similarly, the Latin nōmen included both nouns (substantives) and adjectives, as originally did the English word noun, the two types being distinguished as nouns substantive and nouns adjective. (The word nominalis now sometimes used to denote a class that includes both nouns and adjectives.)

Many European languages use a cognate of the word substantive as the basic term for noun (for example, Spanish sustantivo, "noun"). Nouns in the dictionaries of such languages are demarked by the abbreviation s. or sb. instead of n, which may be used for proper nouns instead. In English, some modern authors use the word substantive to refer to a class that includes both nouns (single words) and noun phrases (multiword units, also called noun equivalents).[8] It can also be used as a counterpart to attributivewhen distinguishing between a noun being used as the head (main word) of a noun phrase and a noun being used as a noun adjunct. For example, the noun knee can be said to be used substantively in my knee hurts, but attributively in the patient needed knee replacement.

Nouns have sometimes been defined in terms of the grammatical categories to which they are subject (classed by gender, inflected for case and number). Such definitions tend to be language-specific, since nouns do not have the same categories in all languages.

Nouns are frequently defined, particularly in informal contexts, in terms of their semantic properties (their meanings). Nouns are described as words that refer to a person, place,thing, event, substance, quality, quantity, etc. However this type of definition has been criticized by contemporary linguists as being uninformative.[9]

There have been offered several examples of English-language nouns which do not have any reference: drought, enjoyment, finesse, behalf (as found in on behalf of), dint (in dint of), and sake (for the sake of).[10][11][12] Moreover, there may be a relationship similar to reference in the case of other parts of speech: the verbs to rain or to mother; many adjectives, like red; and there is little difference between the adverb gleefully and the noun-based phrase with glee.

Linguists often prefer to define nouns (and other lexical categories) in terms of their formal properties. These include morphological information, such as what prefixes or suffixesthey take, and also their syntax – how they combine with other words and expressions of particular types. Such definitions may nonetheless still be language-specific, since syntax as well as morphology varies between languages. For example, in English it might be noted that nouns are words that can co-occur with definite articles (as stated at the start of this article), but this would not apply in Russian, which has no definite articles.

There have been several attempts, sometimes controversial, to produce a stricter definition of nouns on a semantic basis. Some of these are referenced in the Further readingsection below.