Using Hyphens in Compound Nouns, Adjectives and Verbs
Hyphens are often used to form compound nouns, adjectives and verbs in the English language, but not in all cases. In fact, the appearance of hyphens in compound constructions can seem unpredictable and inconsistent to authors and readers who do not understand the principles of their use. As a result, hyphens are frequently misused even by successful academic and scientific writers and can be among the issues with language that cause acquisitions proofreaders to reject papers submitted to them for publication or at least return them with requests for revisions before they can be seriously considered. It is therefore important to understand how hyphens should be used to form compounds correctly and effectively and to apply that knowledge whenever you are preparing your work for publication.
Hyphens are sometimes used in compound nouns, but do keep in mind that compound nouns can be open, hyphenated or closed, with some having predominant forms and others appearing (correctly) in all three forms. The word ‘airstream’ serves as a good example: it is a frequently used form and certainly correct, but so are ‘air-stream’ and ‘air stream,’ with the key being to use one form consistently throughout a document. However, there is also a tendency in English to avoid hyphens in noun compounds, with the preference being one word in American English (airstream) and two words in British English (air stream). Generally speaking, then, noun compounds do not require hyphens, but if the text is unclear or could be potentially misleading, a hyphen should certainly be used: ‘decision making,’ for instance, would normally not use a hyphen, but when an adjective such as ‘quick’ appears before it, the intended meaning may be enhanced by an added hyphen (quick decision-making).
Hyphenation is more common when compounds act as modifiers or adjectives, particularly when the modifying compound precedes the noun it modifies. There are exceptions in such cases, with proper names such as ‘Great Britain’ and compounds formed from an adverb ending in ‘-ly’ and a following adjective (such as ‘carefully engineered’) not using hyphens. Otherwise, hyphenation is never strictly incorrect. However, it is also not always required. There is a difference, for instance, between modifying compounds that contain an adjective (‘mass produced’ and ‘low level’) and compounds that contain nouns only (‘student nurse’ and ‘master mason’). Both types of compound modifiers can be hyphenated when they appear before nouns, as they do in ‘a low-level executive’ and ‘a student-nurse position,’ but the first type should always be hyphenated, whereas the second type does not strictly require a hyphen, with ‘master mason John’ and ‘a student nurse position’ both being correct.
As a general rule, neither type of modifying compound – with or without an adjective in its makeup, that is – requires hyphenation when it appears after the noun it modifies: ‘the book is well known,’ for instance, and ‘John is a master mason’ are both correct. Modifying phrases use the same general pattern of hyphenation when preceding a noun and an open structure when following the noun, so correct forms are ‘up-to-date research’ and ‘the research was up to date.’ In some cases the most familiar phrases are hyphenated even when they appear after the noun, as in ‘her approach was matter-of-fact,’ so checking phrases of this kind in a good dictionary can prove helpful.
As I suggested above, there are exceptions to these general rules. Hyphens are never used in certain compounds whether they appear before or after a noun. These include capitalised compounds and proper names (British Library manuscripts), compound scientific terms (sodium chloride solution) and adjectival compounds in which the first word is an adverb ending in ‘-ly’ (an environmentally sound policy). However, a hyphen is used in adjectival compounds when the second word is an adverb ending in ‘-ly,’ particularly if the compound appears before the noun it modifies, as it does in ‘a user-friendly web site.’
Finally, hyphens tend to be used in verbs formed from two-word noun compounds, so ‘to cross-reference’ is the verb derived from ‘a cross reference.’ Conversely, a noun formed from a phrasal verb is either hyphenated or written as a single word: the verb ‘to back up’ thus becomes the noun ‘back-up’ or ‘backup.’
