Hyphens

The word “hyphen” comes from Greek and literally means “under one”. It describes the hyphen’s function: making two or more words into one – joining them – when there might be some ambiguity otherwise. The classic example of this is “extra-marital sex”. With the hyphen it means adultery, without the hyphen it suggests a happy marriage. The principle is a simple one. When two words are being used as a single adjective or a single noun, they can be hyphenated. For instance, if you talk about keeping an eye on the long term, you would not use a hyphen. “Long” is the adjective and “term” is the noun – there is no possible confusion.On the other hand, if you take a long-term view, you hyphenate – because the two words “long” and “term” are being used as a single adjective.

To decide where the hyphen goes, you just need to work out which part is the adjective and which the noun. Take the example “two-digit codes”. Are we talking about “digit codes” of which there are two? No. Are we talking about codes that can be described as “two-digit”? Yes. So “two-digit” is the adjective, and the hyphen joins its two words together.

People tend to have problems when they come to phrases such as “set up”. Again, the principle is simple. If you’re using the phrase as a verb (it’s called a phrasal verb), there’s no need to hyphenate: “I’ve been set up.” If you’re using the phrase as a noun, you need a hyphen: “This is a set-up”. And if you’re using the phrase as an adjective, you also need a hyphen: “We need to cover our set-up costs.”

Combinations of adverbs and adjectives shouldn’t be hyphenated: a “rapidly flowing river” and a “cleverly argued report” are both right because there is no possibility of ambiguity.

 Hyphens are also used in:

• Fractions:        two-thirds, three-quarters
• Separating identical letters: co-operation, book-keeping
• Preventing misunderstanding: presenting something again is ‘re-presenting’, with the hyphen distinguishing it from the word ‘representing’
• Ranges – see the separate entry