Compound nouns

What is a compound noun?

Compound nouns are words that name a variety of things (people, animals, objects, places, phenomena, etc.) by combining two other words together, usually one noun with another noun or an adjective. New words from the compound noun factory make their debuts in our dictionaries every year: words like coalface.

These nouns can be formed by fusing two nouns (coffee table), an adjective and a noun (blackmail), a verb and a noun (swimming pool), a noun and a verb (sunrise), a verb and a preposition (lie-in), a noun and prepositional phrase (brother-in-law), a preposition and a noun (underpants), or a noun and an adjective (mouthful).

German-speakers are famous for this, whipping up Sauerkraut (words for sour and vegetable) or bolting together some Schadenfreude (words for hurt and joy); there are not shy of whipping out the glue and bonding two or more words together to define things as accurately as they can. This must be why they seem to have a word to define every nuanced thing. The longest word in every day German is Rechtsschutzversicherungsgesellschaften, which means ‘legal protection insurance companies’, i.e. companies that provide insurance for legal protection.

There is no clear rule about how these newly minted words should be written: sometimes the decision makers leave them separate; sometimes the decision-makers hyphenate the words; and sometimes the proofreaders decide to round the words together.

An unofficial sliding scale that can be observed, however; as the combinations become more familiar to readers, they tend to graduate from separate words through hyphenation to seamlessly being joined. In the example above, we English speakers are generally not as familiar with decision-makers to make that last step, but proofreaders have and scriptwriters too.

Another point to remember about compound nouns is that if the words are left separate accidentally, the results can be confusing. For example, a greenhouse is made mostly of sheets of glass, whereas a green house might be mostly timber or brick but be partly painted green. Likewise, a blackbird (the bird species Turdus merula) is a black bird, but not all black birds are blackbirds.

Some very familiar compound nouns, such as Christmas tree or black pudding, are still spelt with separate words: these are known as open or spaced compound nouns.

What’s a compound noun? Perhaps it should be a compoundnoun.

Examples of compound nouns

combination compound noun
noun + noun basketball
adjective + noun software
verb + preposition run-up
noun + prepositional phrase hole-in-the-wall (cash machine)