Noun phrases

A noun phrase or nominal phrase (abbreviated NP) is a phrase which has a noun (or indefinite pronoun) as its head word, or which performs the same grammatical function as such a phrase. Noun phrases are very common cross-linguistically, and they may be the most frequently occurring phrase type.

Noun phrases often function as verb subjects and objects, as predicative expressions, and as the complements of prepositions. Noun phrases can be embedded inside each other; for instance, the noun phrase some of his constituents contains the shorter noun phrase his constituents.

In some more modern theories of grammar, noun phrases with determiners are analyzed as having the determiner rather than the noun as their head; they are then referred to as determiner phrases.

Some examples of noun phrases are underlined in the sentences below. The head noun appears in bold.

Noun phrases can be identified by the possibility of pronoun substitution, as is illustrated in the examples below.

A string of words that can be replaced by a single pronoun without rendering the sentence grammatically unacceptable is a noun phrase. As to whether the string must contain at least two words, see the following section.

Traditionally, a phrase is understood to contain two or more words. The traditional progression in the size of syntactic units is word < phrase < clause, and in this approach a single word (such as a noun or pronoun) would not be referred to as a phrase. However, many modern schools of syntax – especially those that have been influenced by X-bar theory – make no such restriction. Here many single words are judged to be phrases based on a desire for theory-internal consistency. A phrase is deemed to be a word or a combination of words that appears in a set syntactic position, for instance in subject position or object position.

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