Compound nouns

Words can be combined to form compound nouns. These are very common, and new combinations are invented almost daily. They normally have two parts. The first part tells us what kind of object or person it is, or what its purpose is. The second part identifies the object or person in question. Compound nouns often have a meaning that is different, or more specific, than the two separate words.

First part: type or purpose Second part: what or who Compound noun
police man policeman
boy friend boyfriend
water tank water tank
dining table dining-table

You have noticed that the compound noun can be written either as a single word, as a word with a hyphen, or as two words. There are no clear rules about this. A good rule of thumb is to write the most common compound nouns as one word, and the others as two words.

The elements in a compound noun are very diverse parts of speech.

Compound elements Examples
noun + noun bedroom
water tank
motorcycle
printer cartridge
noun + verb rainfall
haircut
train-spotting
noun + adverb hanger-on
passer-by
verb + noun washing machine
driving licence
swimming pool
verb + adverb lookout
take-off
drawback
adverb + noun onlooker
bystander
adjective + verb dry-cleaning
public speaking
adjective + noun greenhouse
software
redhead
adverb + verb output
overthrow
upturn
input
Pronunciation

Stress is important in pronunciation, as it distinguishes between a compound noun and an adjective with a noun. In compound nouns, the stress usually falls on the first syllable.

Examples
  • a 'greenhouse = place where we grow plants (compound noun)
  • a green 'house = house painted green (adjective and noun)
  • a 'bluebird = type of bird (compound noun)
  • a blue 'bird = any bird with blue feathers (adjective and noun)