A noun phrase is a phrase with a noun as its Head, e.g. some foxes, foxes with bushy tails. Some grammarians recognise one-word phrases, so that foxes are multiplying would contain the noun foxes acting as the head of the noun phrase foxes.
- Adult foxes can jump. [adult modifies foxes, so adult belongs to the noun phrase]
- Almost all healthy adult foxes in this area can jump. [all the other words help to modify foxes, so they all belong to the noun phrase]
See also expanded noun phrase.