both house and big house are N-bars, while the big house is a noun phrase. In the sentence I like big houses, both houses and big houses are N-bars, but big houses also functions as a noun phrase (in this case without an explicit determiner).

In some modern theories of syntax, however, what are called "noun phrases" above are no longer considered to be headed by a noun, but by the determiner (which may be null), and they are thus called determiner phrases (DP) instead of noun phrases. (In some