The behavior of proper nouns is illustrated in the first two columns of the table above. Most proper nouns behave like Fred in column 1. They do not allow a plural form (*Evelyns, *Cairos, etc.) and do not appear with determiners (*a Baltimore, *some Evelyn, etc.). Some proper nouns do appear in a plural form and with a determiner: the Netherlands in column 2, for example. But these proper nouns still behave differently from common nouns. There is no contrast in number; the Netherlands cannot be made singular (*the Netherland), and the determiner cannot be varied the way it can with ordinary common nouns:
(1) *I went to Netherlands.
(2) *I only had time to visit a Netherland.
There are also singular proper nouns that take an article, such as the Kremlin. Here too, there is no plural counterpart (*the Kremlins) and the article cannot be varied.
Expressions like Princeton University or the United States of America are frequently called proper nouns as well, but this a somewhat misleading simplification. Remember that noun is a category label for an individual word. Strictly, the proper nouns here are Princeton and America. University and states are common nouns, and united is an adjective. The complete expressions are proper names. A proper name contains a proper noun, and may contain other elements. If there is only a proper noun in the NP, it is still a proper name.
In some situations, a proper noun can be converted to a common noun and can be plural or take a determiner:
Here, a proper name has been made to stand for a whole class, and hence behaves like other common nouns.
Proper names have a few structural peculiarities. We won't go into them in detail in this course, but we will discuss the patterns that may cause problems for your analysis when we review NP structure at the end of the chapter.
 The proper noun does not need to be the head of the proper name. For example, in the United States of America, the head is states.