Double-click on any word and see its definition from Cambridge Dictionaries Online.

Practise with a grammar game

While there are different ways that compound nouns can be formed (using adjectives, prepositions, apostrophes, etc.), we are going to concentrate here on the noun + noun form:

bed + room = bedroom; police + officer = police officer, etc.

There are three different ways to form this type of compound noun:

"the closed form, in which the words are melded together, such as firefly …keyboard …notebook;

the hyphenated form, such as sky-scraper … ski-boot … girl-friend;

and the open form, such as post office … history book … mineral water."

Just exactly how and why these three forms exist is not exactly clear, but it seems likely that the process will begin with two words, become hyphenated after a time, and then eventually end up as just one word. It is curious that even good dictionaries sometimes disagree with how compound nouns should be spelt!

In these noun + noun structures, the first noun behaves similarly to an adjective, in that it describes or modifies the second noun:

A car park is a place for parking cars;
A history book is a book of history.

Another issue to consider is pronunciation. Most noun + noun structures have the main stress on the first word:

post office; car park; fruit juice.

There are, however, quite a few exceptions to this rule:

meat pie; garden table.

This type of compound noun is commonly used to classify particular types of things, and especially for well-known "classes" of things:

Compare a maths book; a geography book; a physics book, which are all books commonly found in schools, to a book about pollution, NOT a pollution book.

We have provided a very basic explanation of this use of compound nouns, an area of grammar that many people consider to be amongst the most difficult.

For further information, and some quizzes, please see the following web sites:

Compound nouns explained:

http://www.edufind.com/english/grammar/NOUNS4.cfm

Quiz

http://www.aitech.ac.jp/~iteslj/quizzes/vm/m-cm.html