The Hyphen

The hyphen (-) is the small bar found on every keyboard. It has several related uses; in every case, it is used to show that what it is attached to does not make up a complete word by itself. The hyphen must never be used with white spaces at both ends, though in some uses it may have a white space at one end.

Most obviously, a hyphen is used to indicate that a long word has been broken off at the end of a line:

We were dismayed at having to listen to these utterly inconse-
quential remarks.

You should avoid such word splitting whenever possible. If it is unavoidable, try to split the word into two roughly equal parts, and make sure you split it at an obvious boundary. Do not write things like


The first two of these are not broken at syllable boundaries, while the third is broken into two very unequal pieces. If you are in doubt as to where a word can be split, consult a dictionary. Many good dictionaries mark syllable boundaries to show you where words can be hyphenated. Some publishers even bring out hyphenation dictionaries containing no other information. Best of all, many word processors will perform hyphenation automatically, and you won't have to worry about it. In any case, note that a hyphen in such a case must be written at the end of its line, and not at the beginning of the following line.

The hyphen is also used in writing compound words which, without the hyphen, would be ambiguous, hard to read or overly long. Here, more than anywhere else in the whole field of punctuation, there is room for individual taste and judgement; nevertheless, certain principles may be identified. These are:

(1) Above all, strive for clarity;
(2) Don't use a hyphen unless it's necessary;
(3) Where possible, follow established usage.

On this last point, consult a good dictionary; Collins or Longman is recommended, since the conservative Chambers and Oxford dictionaries frequently show hyphens which are no longer in normal use.

Should you write land owners, land-owners or landowners? All are possible, and you should follow your judgement, but I prefer the third, since it seems unambiguous and easy to read, since it avoids the use of a hyphen and since this form is confirmed by Longman and Collins as the usual one (while Chambers, predictably, insists on the hyphenated form).

What about electro-magnetic versus electromagnetic? Collins and Longman confirm that only the second is in use among those who use the term regularly, but again Oxford clings stubbornly to the antiquated and pointless hyphen.

On the other hand, things like *pressurecooker, *wordprocessor and *emeraldgreen are impossibly hard on the eye; reference to a good dictionary will confirm that the established forms of the first two are pressure cooker and word processor, while the last is emerald green or emerald-green, depending on how it is used (see below).

The hyphen is regularly used in writing so-called "double-barrelled" names: José-María Olazábal, Jean-Paul Gaultier, Claude Lévi-Strauss, Philip Johnson-Laird. However, some individuals with such names prefer to omit the hyphen: Jean Paul Sartre, Hillary Rodham Clinton. You should always respect the usage of the owner of the name.

Now here is something important: it is usually essential to hyphenate compound modifiers. Compare the following:

She kissed him good night.
She gave him a good-night kiss.

The hyphen in the second example is necessary to show that good-night is a single compound modifier. Without the hyphen, the reader might easily be misled:

Here the reader might be momentarily flummoxed into thinking that she had given him some kind of "night kiss", whatever that means. Here are some further examples:

Her dress is light green.
She's wearing a light-green dress.
This book token is worth ten pounds.
This is a ten-pound book token.
She always turned up for the parties at the end of term.
She always turned up for the end-of-term parties.
This essay is well thought out.
This is a well-thought-out essay.
Her son is ten years old.
She has a ten-year-old son.

Use hyphens liberally in such compound modifiers; they are often vital to comprehension: a light-green dress is not necessarily a light green dress; our first-class discussion is quite different from our first class discussion; a rusty nail cutter is hardly the same as a rusty nail-cutter; a woman-hating religion is utterly different from a woman hating religion; and a nude-review producer is most unlikely to be a nude review producer! You can mislead your reader disastrously by omitting these crucial hyphens: She always turned up for the end of term parties does not appear to mean the same as the hyphenated example above (example adapted from Carey 1958: 82). So make a habit of hyphenating your compound modifiers:

a long-standing friend
not *a long standing friend
well-defined rules
not *well defined rules
a copper-producing region
not *a copper producing region
a low-scoring match
not *a low scoring match
little-expected news
not *little expected news
a green-eyed beauty
not *a green eyed beauty
a rough-and-ready approach
not *a rough and ready approach
a salt-and-pepper moustache
not *a salt and pepper moustache
a far-ranging investigation
not *a far ranging investigation
her Swiss-German ancestry
not *her Swiss German ancestry
her new-found freedom
not *her new found freedom
the hang-'em-and-flog-'em brigade
not *the hang 'em and flog 'em brigade

The correct use or non-use of a hyphen in a modifier can be of vital importance in making your meaning clear. Consider the next two examples:

The earliest known hominid was Homo habilis.
The earliest-known hominid was Homo habilis.

These do not mean the same thing at all. The first means that, of all the hominids we know about, H. habilis was the earliest one to exist (but not necessarily the first one we knew about). The second means that, of all the hominids, H. habilis was the first one we knew about (but not necessarily the first one to exist). Effectively, the first sentence includes the structure [earliest] [known hominid], while the second includes the structure [earliest-known] [hominid]. Again, these two sentences would be pronounced differently, but the pronunciation difference is lost in writing; hence accurate punctuation is essential if you are not going to mislead your reader utterly. Punctuation is not a matter for personal taste and caprice, not if you want your readers to understand what you've written. (As it happens, the first statement is true, but the second one is false.)

A compound modifier may also require a hyphen when it apears after the verb. Here is a splendid example from Carey (1958): Her face turned an ugly brick-red appears to mean something very different from Her face turned an ugly brick red.

Old-fashioned usage, especially in Britain, favours excessive hyphenation, producing such forms as to-day, co-operate, ski-ing, semi-colon and even full-stop; such hyphens are pointless and ugly and should be avoided. Much better are today, cooperate, skiing, semicolon and full stop: don't use a hyphen unless it's doing some real work.

Prefixes present special problems. She's repainting the lounge seems unobjectionable, but She's reliving her childhood is possibly hard to read and should perhaps be rewritten as She's re-living her childhood. And She re-covered the sofa [= `She put a new cover on the sofa'] is absolutely essential to avoid confusion with the entirely different She recovered the sofa [= `She got the sofa back']. The chemical term meaning `not ionized' is routinely written by chemists as unionized, but, in some contexts, you might prefer to write un-ionized to avoid possible confusion with the unrelated word unionized `organized into unions'. Use your judgement: put a hyphen in if you can see a problem without it, but otherwise leave it out. Here are a few examples of good usage:

but mini-aircraft
but non-negotiable
but pre-empt
but anti-aircraft

The hyphen is written only when the word would be hard to read without it: *nonnegotiable, *preempt. As always, consult a good dictionary if you're not sure.

Observe, by the way, that a prefix must not be written as though it were a separate word. Thus all the following are wrong:

*post war period
*non communist countries
*mini computer
*anti vivisectionists

There are three cases in which a hyphen is absolutely required after a prefix. First, if a capital letter or a numeral follows:

non-EC countries
un-American activities
pre-Newtonian physics
anti-French feeling
post-Napoleonic Europe
pre-1500 English literature

Second, if the prefix is added to a word which already contains a hyphen:

non-bribe-taking politicians
his pre-globe-trotting days
non-stress-timed languages
an un-re-elected politician

Your reader cannot be expected to take in at a glance some indigestible glob like *his preglobe-trotting days or *an unre-elected politician.

Third, if the prefix is added to a compound word containing a white space. In this case, the white space itself must be replaced by a hyphen to prevent the prefixed word from becoming unreadable:

seal killing
but anti-seal-killing campaigners
twentieth century
but pre-twentieth-century music
cold war
but our post-cold-war world

Again, your readers will not thank you for writing something like *antiseal killing campaigners or *our postcold-war world (or, still worse, *our postcold war world, a piece of gibberish I recently encountered in a major newspaper) . Who are these campaigners who kill antiseals, whatever those might be, and what is a war world and what is special about a postcold one?

In any case, do not go overboard with large and complex modifiers. The cumbersome anti-seal-killing campaigners can easily be replaced by campaigners against seal-killing, which is much easier to read.

The hyphen may also be used in representing ranges of numbers, and occasionally also other ranges. Printed books use a special symbol for this, the en dash (), which is a little longer than a hyphen but still shorter than a full dash. Few keyboards can produce an en dash, however; if yours can't, you should use a hyphen instead (not a dash). A representation of the form X–Y means `from X to Y' or `between X and Y'. Here are some examples:

Steel contains 0.1–1.7 % carbon.
These fossils are 30–35 million years old.
The London–Brighton vintage car rally takes place on Sunday.
The declaration of the Rome–Berlin axis led to the use of the label `Axis powers' for Germany and Italy.

Do not write things like this:

*Steel contains from 0.1–1.7 % carbon.
*Steel contains between 0.1–1.7 % carbon.

These are terrible, since the sense of `from' or `between' is already included in the punctuation.

Finally, the hyphen has one rather special use: it is used in writing pieces of words. Here are some examples:

The prefix re- sometimes requires a hyphen.
The suffix -wise, as in `moneywise' and `healthwise', has become enormously popular in recent years.
The Latin word rex `king' has a stem reg-.

Only when you are writing about language are you likely to need this use of the hyphen. If you do use it, make sure you put the hyphen at the correct end of the piece-of-a-word you are citing ‹ that is, the end at which the piece has to be connected to something else to make a word. And note that, when you're writing a suffix, the hyphen must go on the same line as the suffix itself: you should not allow the hyphen to stand at the end of its line, with the suffix on the next line. Word processors won't do this automatically, and you will need to consult your manual to find out how to type a hard hyphen, which will always stay where it belongs.

There is, however, one very special case in which you might want to write a piece of a word in any kind of text. Consider the following example:

Pre-war and post-war Berlin could hardly be more different.

There is another way of writing this:

Pre- and post-war Berlin could hardly be more different.

This style is permissible, but observe that the now isolated prefix pre- requires a hyphen, since it is only a piece of a word.

The same thing happens when you want to write a piece of a word which is not normally hyphenated, in order to avoid repetition:

Natalie is studying sociolinguistics and psycholinguistics.

This can also be written as follows:

Natalie is studying socio- and psycholinguistics.

The hyphen is also used in writing numerals and fractions.

Copyright © Larry Trask, 1997

Maintained by the Department of Informatics, University of Sussex