Category: Rules

Greek scholars invented the hyphen in about the second century BC. Two thousand years later, we’re still struggling to get it right.

English hyphenation is a mix of logic, convention, and sheer inconsistency. Moreover, as with practically every aspect of the English language, different authorities have different views. The whole thing needs an explanation – which I’m going to attempt.

I’ve broken it into two parts:

• Quick guide – the 10 things a hyphen is used for
• Pro tips – for those who strive for hyphen perfection

But first, a few words about the history and rationale of punctuation marks in writing.

Did you know that in Ancient Greek and Latin, writers didn’t usually put spaces between their words? Don’t ask me why. They just didn’t. They wrote in scriptio continua, a style of writing without spaces or punctuation. And all in capitals. So whatever you read in those days, ITWASLIKEDOINGAWORDSEARCHPUZZLE. You had to figure out where one word ended and the next one started from context and guesswork.

Scriptio continua – image from Wikimedia Commons (public domain)

Then along came a Greek scholar named Dionysius Thrax, who is credited with having invented the hyphen. Sources differ as to the exact origin; some attribute it to an earlier scholar, Aristophanes of Byzantium. What’s clear is that the hyphen developed over time and Dionysius helped to define and document it. Around 150–100 BC, scholars started playing around with some zippy newfangled things they called the komma, the kolon and the periodos and other devices to make script easier to read – like spaces between words. They also came up with the tie mark – a curved punctuation mark placed underneath two words that were meant to be read as one, which would evolve into the hyphen. Late Latin coined “hyphen” from the Greek elements hupo (under) and hen (one).

Perhaps surprisingly, punctuation marks and spaces between words didn’t really catch on until about 700 years later, when Irish and Anglo-Saxon monks and, later, medieval scribes and Renaissance scholars formalised them. But I digress.

Why do we bother with punctuation? And why hyphens in particular?

Punctuation is a courtesy designed to help readers to understand a story without stumbling.

—Lynne Truss, Eats, Shoots & Leaves (quoting from a UK national newspaper’s style book)

Quick guide to the 10 uses of the hyphen

The hyphen is arguably the most versatile and the most frequently misunderstood of the English language’s 14‑or-more punctuation marks (others of which, dear reader, I may cover in future articles). I’ve compiled a list of ten jobs a hyphen can do. You might make it more or fewer than ten depending on how you categorise the uses. I don’t think I’ve missed anything but I’m happy to be corrected if I have.

So here’s your quick guide. A hyphen is used for:

1. Linking words that go together
2. Designating a prefix
3. Providing clarity and aiding pronunciation
4. Indicating a missing element
5. Indicating a spelled-out word
6. Expressing numbers and fractions
7. Writing double-barrelled names and compound place names
8. Dividing a word at the end of a line
9. Denoting a span of dates or values
10. Separating clauses

1. Linking words that go together

Do you know what a man eating tiger is? If you write it like that – with no hyphen – it means a man who is eating tiger [meat].

If you want to describe a tiger that preys on humans, the term is man‑eating tiger. “Man-eating” is a compound adjective.

The same logic applies to many other compounds. Hyphens tell the reader, “Read these words together.”

• Some compounds are always hyphenated: user-friendly, jack-of-all-trades, and mother-in-law are three rather random examples that spring to mind.
• Some compounds are never hyphenated, like pro bono, fully equipped, or high school.
• For many compounds, it depends: long term vs long-term; third party vs third‑party. You hyphenate them when they function as adjectives (a long-term plan, a third-party agreement), but not otherwise (in the long term, negotiating with a third party).

2. Designating a prefix

Some words with prefixes take hyphens; some don’t. There is no hard-and-fast rule. Hyphenated prefixes are more common in UK English than in North American English – compare non-profit (UK) with nonprofit (US). New words often start life with a hyphenated prefix but drop the hyphen as they become more established; for example, e-mail has largely become email.

3. Providing clarity and aiding pronunciation

Some words need a hyphen to avoid ambiguity or to aid readability or pronunciation, for example:

• re-cover (what an upholsterer does) to distinguish from recover (what you do, hopefully, after you’ve been ill)
• re-sent (sent again) to distinguish from resent (begrudge)
• re-enter for better readability than reenter
• co-op (a workers’ cooperative) to distinguish from coop (a poultry cage)

4. Indicating a missing element – suspended hyphens

You can use a hyphen to indicate a missing word. For example, you could shorten the phrase first-prize and second-prize winners to first- and second-prize winners. This eliminates a bit of repetition. Note the space after the first hyphen in this construction.

5. Indicating a spelled-out word

A compound word made from a letter and a word takes a hyphen: T-shirt, X-ray, H‑bomb, U‑turn. You’d also use hyphens if you were to write a phrase like “The name is Wilkins: W-I-L-K-I-N-S.”

6. Expressing numbers and fractions

Numbers above twenty take hyphens when written out as words: seventy-five, ninety-six, etc. And so do fractions: two-thirds; three-quarters; one-and-a-half.

7. Writing double-barrelled names and compound place names

Most double-barrelled surnames and some compound place names take hyphens.

• Stratford-upon-Avon has hyphens but Kingston upon Thames doesn’t. Why? Well, it’s just one of those things.
• Tim Berners-Lee (inventor of the World Wide Web) has a hyphen but John Logie Baird (inventor of the television) doesn’t – actually Logie is not part of the surname; that’s the main reason.
• Some people have first names with hyphens: Mary-Jane, Billy-Joe, Marie‑Claire, Jean-Marc.

8. Dividing a word at the end of a line

These days you rarely, if ever, need to divide a word manually. That is, unless you’re a professional typesetter – in which case end-of-line hyphenation is crucial for avoiding uneven spacing and the dreaded ‘rivers’ of white space – especially in print. For the rest of us, it’s hardly a concern. Most digital documents are left aligned with a ragged-right edge, so word breaks aren’t an issue. And even if you justify your text (aligning both left and right edges), modern software usually handles spacing automatically and won’t hyphenate words by default.

9. Denoting a span of dates or values

2024-26; 15-30; A-Z; Monday-Friday. You can use a hyphen to indicate a span of dates or values. Many style guides specify an unspaced en dash for this purpose. I’d say either a dash or a hyphen is fine as long as you’re consistent.

10. Separating clauses

You can use a dash – like this – to separate clauses within a sentence – making it easier to read. A dash is longer than a hyphen. In UK English we tend to use the en dash with a space before and after. US English usually uses the even longer em dash, unspaced. A spaced hyphen is sometimes used instead of a dash. This is not really a correct usage.

11. Oh, and…

Hyphens are also used in URLs, filenames, email addresses, social media handles, programming languages, and command-line interfaces. I mention this in passing for the sake of completeness. I think that’s just about everything.

Pro tips for hyphenation perfection

We’ve seen that some word pairs always take hyphens and others never take them, and for others again it just depends. But which ones? Here is my best attempt at a near-definitive set of guidelines.

Fixed non-hyphenated compounds

Some compounds never take hyphens, even when used adjectivally. For example: post office, high school, income tax, shopping centre, coffee table, hair dryer, fire engine. Hyphens would look unnatural in these phrases, no matter how they’re used:

• post office queue
• shopping centre management
• coffee table book
• fire engine red

Compound adjectives before or after a noun

When two or more words are used as a single adjective before a noun, they usually take a hyphen: high-risk investment, well-known author, full-time job, like-for-like figures. However, when the same compound adjective follows the noun, the hyphen is usually dropped: the job is full time, the author is well known, the investment is high risk, the figures are like for like.

Adjective compounds with -ly adverbs

Adverbs ending in -ly that modify adjectives are never hyphenated: a highly skilled worker, a beautifully designed room. This is because the adverb can’t be mistaken as modifying anything other than the adjective.

Latin terms and foreign phrases

Latin phrases like ad hoc, pro bono, and bona fide are not hyphenated, even when used adjectivally: an ad hoc solution, a pro bono case. The same applies to various Italian and French terms: a cappella singing, en masse evacuation.

Hyphenated prefixes

Some prefixes are used with or without a hyphen depending on what they’re being used for. Pro is a good example. When it means “in favour of” it’s typically hyphenated: pro-growth, pro-business, pro-European; when it’s part of a Latin phrase like pro bono, pro rata, or pro tempore it’s two words open.

You’d always hyphenate a prefix that comes before a proper noun: pan-European; anti-American; post-Renaissance. Unless, that is, it’s become one solid word over time, like transatlantic.

Words that have become solid with time

Many words (like transatlantic) that were originally hyphenated or two separate words have become solid over time: multilingual, email, website, database.

 

I hope these notes clarify things for you. Ultimately, though, English hyphenation remains a mix of logic, convention, and sheer inconsistency. So for best results your organisation would probably do well to adhere to a comprehensive A-to-Z word list as part of a style guide.