Hyphens and Dashes: Their Difference and Uses

A dash is a dash is a dash. And hyphens and dashes are one and the same (cliché there).

Right? Wrong.

Unless you’ve done some proofreading or have had some experience with publishing, you probably wouldn’t have heard of em and en dashes (its not-so-popular sibling). After all, if a hyphen would suffice, why use dashes?

Not until I started my job as a copyeditor in a publishing company about a year ago, I thought hyphen and dashes were essentially the same or maybe somehow different but interchangeable, that they are just two different words used to refer to the same thing. However, as it turned out, hyphens and dashes (em and en) actually have their uses and specific appearance. Pre-PC times, writers made do with two successive hyphens (–) for em dashes on their typewriters.

So what ever did they use in lieu of en dashes? Hyphens, of course.

The use of en and em dashes are thoroughly distinguished from the use of hyphen by the Chicago Manual of Style in chapters 6.80 to 6.96.

As for their appearance, this is how they look like:

Hyphen –

En dash – (CTRL + minus sign on the number board or ALT + 0150 if you don’t have the full keyboard)

Em dash — (CTRL + ALT + minus sign on the number board or ALT + 0151 if you don’t have the full keyboard)

2 em dashes —— (em dashes encoded twice)

3 em dashes ——— (em dashes encoded thrice)

So how are they different and what functions do they serve in technical writing?

Hyphens

Compounds

The hyphen is commonly used in compounds words and names in word divisions.

six-year-old child; a sixty-three-year-old; but he is six years old

great-great-grandchild of the artist

actor-politician Ronald Reagan

“My grandmother is fifty-one.”

two-thirds; three-quarters of the class; one and one-half

For a comprehensive and categorized listing of compound words and whether or not they should be hyphenated, click here.

To Separate Characters

A hyphen is used to separate numbers that are not inclusive, such as telephone numbers, social security numbers, and ISBNs. It is also used—in dialogue, in reference to American Sign Language, and elsewhere—to separate letters when a word is spelled out.

My phone number is 0932-8703-807.

“My name is Kirby Keith. That’s K-I-R-B-Y and K-E-I-T-H.”

A proficient signer can fingerspell X-Y-L-O-P-H-O-N-E in less than two seconds.

Introducing the Less-Known Dashes

The En Dash

The en dash is created by keying keying in CTRL and the minus sign on the number board; however, if you do not have the complete keyboard, you can key in ALT and 0150. It is called an en dash because its length is approximately that of the letter N (capitalized).

Inclusive Numbers

The principal use of the en dash is to connect numbers and, less often, words. In this use it signifies up to and including (or through). For the sake of parallel construction, the word to, never the en dash, should be used if from precedes the first element.

My college years, 2006–2011, were the happiest in my life so far.

We were asked to read pages 116–187 and write a term paper on it.

The real attributes of love is defined in 1 Corinthians 13:1–8..

Every day at 1:00PM–4:00PM, I am usually busy checking all media contacts from other countries..

The London–Paris train leaves at two o’clock

But

She waited at the film center from 6:00 PM to 10:45 PM.

I heard he was dean at the college between 1971 and 1986.

With Nothing Following

An en dash may be used by itself after a date to indicate that something is still going on (for example, if it refers to a person, it means that the person is still alive). No space follows the en dash.

Professor Monroe’s survey (1999–) will cover the subject in the final volume.

Jane Doe (1950–); or Jane Doe (b. 1950)

In Place of a Hyphen

The en dash is used in place of a hyphen in a compound adjective when one of the elements is an open compound or when two or more of its elements are open compounds or hyphenated compounds.

the post–World War II years; not World-War-II years

a hospital–nursing home connection

a nursing home–home care policy

(Nursing home and home care are compound nouns; hence, not hyphenated)

but

non-English-speaking countries

non-wheelchair-bound passengers

(English-speaking and wheelchair-bound are not nouns; hence, hyphenated)

Other Uses

An en dash is used to link a city name to the name of a university that has more than one campus.

West Visayas State University–Himamaylan (LOL)

University of Wisconsin–Madison

The Em Dash

The em dash, often simply called the dash, is the most commonly used dash family member. It is created by keying in CTRL + ALT + minus sign of the number board (or ALT + 0151) and is about the same length as a capital M.

Amplifying or Explaining

An em dash or a pair of em dashes (it sometimes comes with a twin) sets off an amplifying or explanatory element. (Note that commas, parentheses, or a colon may perform a similar function.)

My life needs to change again—otherwise the absurd with a capital A wins.

So why this murder—this kind of murder—of this man, and in that place?

Back home, I write a column for the County Chronicle—a food column to be exact—and while I’m here, I’m continuing to write for the Chronicle.

NOTE: In many instances, commas are enough to set off parenthetical elements. The use of em dashes in place of commas is imperative only in instances where the parenthetical element contains internal punctuation. If commas were used in the original and the use of em dashes is unwarranted, no need to make changes.

Indicating Sudden Breaks

An em dash or a pair of em dashes may indicate a sudden break in thought or sentence structure or an interruption in dialogue.

“I’m not so sure that I—let’s go back to Christophe.” The woman’s middle name was digression, with a capital D.

“Christophe left Friday for Venice for two months. And I already miss him. He is a great friend—kind, witty, interesting—”

“Please slow down. Wait a minute. My beeper just went off.”

If the break belongs to the surrounding sentence rather than the quoted material, the em dashes must appear outside the quotation mark.

“Someday he’s going to hit one of those long shots, and”—his voice turned puffy—“I won’t be there to see it.”

Used in Place of, or with, a Comma

If the context calls for an em dash where a comma would ordinarily separate a dependent clause from an independent clause, the comma should be omitted. But if an em dash is used at the end of quoted material to indicate an interruption, a comma should be used before the words that identify the speaker.

Because the data had not been fully analyzed—the reason for this will be discussed later—the publication of the report was delayed.

but

“I assure you, we shall never—,” Sylvia began, but Mark cut her short.

With Other Punctuation

A question mark or an exclamation point—but never a comma, a colon, or a semicolon, and rarely a period—may precede an em dash.

All at once Richard—can he have been out of his mind?—shook his fist in the ambassador’s face.

Only if—heaven forbid!—you lose your passport should you call home.

The 2- and 3-em Dashes

A 2-em dash represents a missing word or part of a word, either omitted to disguise a name (or occasionally an expletive) or else missing or illegible in quoted or reprinted material. When a whole word is missing, a space appears on both sides of the dash. When only a part of a word is missing, no space appears between the dash and the existing part (or parts) or the word; when the dash represents the end of a word, a normal word space follows it.

“The region gives its —— to the language spoken there.”

Admiral N—— and Lady R—— were among the guests.

David H——h [Hirsch?] voted aye.