A Noun Phrase (NP) is a phrasal syntactic category in which the syntactic head, that is the most important element, is a noun [Lexicon - 3.1.]. An NP can consist of only a noun without any modifiers, such as an Adjective [Lexicon - 3.4.] or a Numeral [Lexicon - 3.10.1]. The following is an example of a noun phrase with only the head noun.
cat
'cat'
An NP can also include one or more modifiers which do not change the basic meaning of the NP but modify it in several ways including definiteness [Pragmatics - 1.2.], quality, quantity, spatial position and origin. A modifier can be a Determiner [Lexicon - 3.6.] described in this chapter in [Syntax – 4.1.], a possessive [Syntax – 4.2.], a numeral [Syntax – 4.3.], an Adjective [Syntax – 4.4.], a quantifier [Syntax – 4.4.] . Also, certain combinations of these [Syntax - Section 4.6.] may occur inside an NP. Below, there is an example of an NP with the head noun sheet_of_paper and a demonstrative determiner this.
this sheet_of_paper
'This sheet (of paper)'
NPs can have a number of grammatical functions [Syntax - 2.2.]. In the following sentence, the NP, [poss(x)1 car], functions as the Subject of the predicate work.
[poss(x)1 car ] work ^ not
'My car isn't running.'
An NP can also function as the object of a postposition. In the following example, [this class] is the object of the postposition for.
[this class] for
'for this class'