Compound nouns

A compound noun is a noun that is formed from two or more words. The meaning of the whole compound is often different from the meaning of the two words on their own. Compound nouns are very common. The main noun is normally the last one.

teapot	headache
washing machine	driving licence
self-control	CD burner

Compound nouns are commonly formed from the following word combinations:

noun + noun,
verb + noun,
adjective + noun,
phrasal verb used as noun,
particle + noun.

noun + noun:	boyfriend	skinhead
verb + noun:	breakfast	grindstone
adjective + noun:	software	hardware
phrasal verb:	a break-in	a take-over
particle + noun:	onlooker	aftershave

The term particle is used for a word which could be either an adverb or a preposition.

Compound nouns can be written:

as one word.

bookcase	wallpaper
birdcage	snowflake

as two words.

post office	fire engine
eye shadow	cough sweets

with a hyphen.

window-cleaner	air-conditioning
lamp-post	tee-shirt

Consult a dictionary to discover how the word is normally written. There are often alternative forms to be found, for example, drop down menu, drop-down menu, and dropdown menu are all currently acceptable forms of the same compound noun.

Nouns as modifiers

The compound noun girlfriend names a special sort of friend. Nouns can also be used as modifiers without forming a compound noun.

a concrete slab	old oak beams
a car mechanic	a store manager

A noun that is used as a modifier has the same function as an adjective. The first noun usually makes the second one more specific, but we do not think of it as part of a combination that forms a new word. See Adjectives for more on modifiers.