Hyphens have many functions, but their main role is to link words (or parts of words). They most commonly appear with compound adjectives, phrasal verbs being used as nouns, and after some prefixes.
Compound adjectives consist of two words that work together to modify a noun form a compound adjective (or compound modifier). When this compound adjective comes before a noun, it needs a hyphen.
Example: compound adjective comes before a noun
The VP for development, who is currently a well-respected economist, oversees the London-based company’s fast-paced expansion.
However, when a compound adjective comes after a noun, it usually does not need a hyphen.
Example: compound adjective comes after a noun
The VP is well respected and her area of responsibility is fast paced.
Also note that compound adjectives that contain an adverb that ends in “ly” are not hyphenated. (Adverbs modify adjectives, verbs, and other adverbs and often answer the question “How?”)
Example: compound adjectives that contain an adverb that ends in “ly”
The company’s highly paid managers are responsible for running largely diverse teams.
Phrasal verbs used as nouns
Phrasal verbs don’t normally require hyphens. However, they do when they are used as nouns.
|Not used as noun||Used as noun|
|The project will start up tomorrow.||The start-up involves many people.|
|The government bailed out the bank.||The bail-out was very controversial.|
|Many states are still building up arms.||The arms build-up is a great threat.|
Few fixed rules exist about whether hyphens should be used to connect prefixes (such as un, pre, and multi). Practices also vary over time; as a term becomes more common, the hyphen usually disappears (such as e-mail, which has gradually turned into email). If in doubt, use a dictionary.
Also bear in mind that prefixes are more frequently hyphenated in British English (e.g. sub-section) than in American English (e.g. subsection).
One firm guideline is to always hyphenate prefixes that come before a capital letter, numeral, or date.
|The anti-UN faction was very vocal during the mid-March 1970 discussions.||An un-Christian attitude was uncommon.|
|The sculpture is pre-16th century.||Inter-African cooperation is growing.|
|The events all occurred post-Gulf War.||Presidents are often in their mid-50s.|
Pay careful attention to meaning!
Sometimes the absence of a hyphen makes it unclear what you are trying to say.
|Possible interpretation||Clearer option|
|Five year old girls||Girls who are five years old.|
Five girls who are one year old.
Five year-old girls
In addition, sometimes a phrase means something completely different when a hyphen is added.
|Long standing tradition||A tradition of standing for a long time.|
Ex: The Quaker religion has a long standing
tradition in its worship services.
|Long-standing tradition||A tradition that has existed a long time.|
Ex: Lighting candles is a long-standing tradition.
|Recovered book||A book that one has gotten back.|
Ex: The library recovered the book from its patron.
|Re-covered book||A book that has a new cover on it.|
Ex: The librarian re-covered the damaged book.
Hyphens are tricky, even for experienced writers. In addition to the above, keep the following tips in mind:
- Be consistent in how you hyphenate related items. For instance, if you refer to sub-chapters, you should also refer to sub-sections and sub-questions. (The alternative: subchapters, subsections, and subquestions.)
- Follow standard usage rules as much as you can, paying particular attention to what most often appears in your secondary literature. And don’t be afraid to look things up if you are unsure!
- Avoid overdoing it. Most styles (including APA) say that hyphens should only be used when they are truly needed.
- Don’t get hyphens confused with their longer relative, the dash.
- Oxford Dictionaries: Language matters. (n.d.). Hyphen (-). Retrieved from http://www.oxforddictionaries.com/words/hyphen
- Trask, L. (1997). The Hyphen. Retrieved from http://www.sussex.ac.uk/informatics/punctuation/hyphenanddash/hyphen