A compound noun is a fixed expression which is made up of more than one word and functions as a noun. Such expressions are frequently combinations of two nouns, e.g. address book, human being, science fiction. A number of compound nouns are related to phrasal verbs and these are dealt with in Unit 14.
Compound nouns may be written as two words, e.g. tin opener, bank account, or they may be written with a hyphen instead of a space between the words, e.g. pen-name, baby-sitter. Some expressions are occasionally written with a hyphen and occasionally as two separate words. For instance, both letter box and letter-box are correct. Sometimes they may be written as one word, e.g. earring.
Compound nouns may be countable, uncountable or only used in either the singular or the plural. There are examples of each of these types below. Check that you understand the meanings of each of the expressions listed. If you understand both elements of the expression, the meaning will usually be clear. If the meaning is not fairly obvious, then it is provided below.
Usually the main stress is on the first part of the compound but sometimes it is on the second part. The word which contains the main stress is underlined in the compound nouns below. Here are some examples of common countable compound nouns.
alarm clock assembly line blood donor book token
burglar alarm contact lens credit card handcuffs
heart attack package holiday pedestrian crossing shoe horn
tea-bag windscreen windscreen wiper youth hostel
Here are some examples of common uncountable compound nouns. These are never used with an article.
air-traffic control birth control blood pressure cotton wool
data-processing family planning food poisoning pocket money
income tax junk food mail order hay fever (allergy to pollen)
Here are some examples of common compound nouns used only in the singular.
arms race (countries wanting most powerful weapons) death penalty
generation gap labour force
mother-tongue sound barrier
greenhouse effect welfare state
brain drain (highly educated people leaving country to work abroad)
Here are some examples of common compound nouns used only in the plural.
grass roots luxury goods human rights kitchen scissors
race relations roadworks sunglasses traffic lights