Spotlight on CMOS 6.75–94
Most readers know that hyphens connect groups of words or numbers whereas dashes set things off. But from there it tends to get a little fuzzy. For example, which key do you press to get the dash? Is there more than one kind of dash? . . . What about minus signs?
Most copyeditors, on the other hand, will usually know their way around hyphens and dashes. But when it comes to knowing precisely which type of miniature horizontal line is needed for which context, most of us can use the occasional refresher.
We’ll start with the basics, and then we’ll review a few of the lesser-known varieties.
Though it can be considered as a variety of dash, a hyphen, strictly speaking, is the punctuation mark that appears between words in certain compound constructions, as in the phrase well-edited manuscript or the number fifty-three.
Hyphens may also appear as separators between digits in phone numbers and other numeric strings, as in 978-0-226-28705-8, the International Standard Book Number, or ISBN, for the seventeenth edition of The Chicago Manual of Style.
When consecutive digits express a range, however, they are separated in Chicago style not by hyphens but by en dashes, as in the range 3–5 (“three to five”). En dashes also step in for hyphens in certain complex compounds like “pre–Civil War.” It’s usually up to copyeditors rather than authors to apply such dashes (by replacing hyphens with en dashes as needed).*
More commonly, dash refers to the punctuation that’s used to set something off from the surrounding text (much like parentheses). In Chicago style, such dashes consist of em dashes—like this—with no space before or after. In British style, spaced en dashes – like this – are more common.
‑ (hyphen-minus, U+002D)
– (en dash, U+2013)
— (em dash, U+2014)
The shortest of the three, the hyphen is the only one that gets its own key on standard keyboards. On modern QWERTY keyboards, the hyphen key is to the right of the zero.
The Unicode name for the hyphen—hyphen-minus—itself includes a hyphen. The name reflects the fact that this character was interchangeable with the minus sign (which we’ll get to in a moment) before the Unicode Standard was first published (in 1991).
Because it’s the one on most keyboards, lots of people use the hyphen as a dash ‐ like that, with a space on either side‐‐or like that, with two hyphens (or sometimes three), typically without spaces. One of the first things many copyeditors do—often before editing begins—is to replace these hyphens-as-dashes with em (or en) dashes.
True dashes—of either the en or em variety—would probably be more popular if they had their own dedicated key. But they don’t, so you have to do a little extra work to get to them.
On a physical keyboard, dashes can be inserted from a menu for special characters or by using keystrokes. On a PC, Alt+0150 will produce an en dash and Alt+0151 an em dash (using the numeric keypad); in Microsoft Word, you can use the hyphen key on the numeric keypad (where it is often referred to as a minus key) in combination with the Ctrl key (en dash) or the Ctrl and Alt keys (em dash). On a Mac, the keys are Option-Hyphen (en dash) and Option-Shift-Hyphen (em dash).
On a virtual keyboard (as on a mobile phone or a tablet), an em dash is typically inserted by holding down the hyphen and then choosing the longest of several options; the en dash can be inserted in the same way (where it would usually be the second-longest option).
By default, Microsoft Word will convert a double hyphen to an em dash; in Google Docs, double and triple hyphens become en and em dashes, respectively. But many editors who work in those programs turn such automation off lest it step in where it’s not wanted.
A minus sign looks like an en dash. But even though most of us can’t tell the difference at a glance between, for example, −3 and –3 (the minus sign is in the first one), it’s important to use the right mark in the right context. For one thing, a minus sign is designed to line up with the horizontal part of a plus sign regardless of font.
In Unicode, the minus sign is U+2212. In Word or Docs, you can use the menu for special characters or symbols. Here’s the Symbol dialog box in MS Word (accessed via the Insert tab):
That screenshot is from Word 365 for a PC. Note the Unicode number. Word for the PC will also let you insert a minus sign—or any Unicode character—by typing the number directly into your document and then pressing Alt+X. On a Mac, the menu for special characters will be a bit different (and the trick with X won’t work).
2-em and 3-em Dashes‡
In Chicago style, the 2-em dash is reserved for missing or illegible text from a quoted source or text that needs to be obscured for some reason, as in “Admiral N—— and Lady R—— were among the guests” (where “N——” and “R——” stand in for names); note the space after each 2-em dash in the example sentence. See CMOS 6.93.
The 3-em dash is used in bibliographies, where it stands in for the name of an author in successive works by that same author (though some publishers prefer to repeat the name; see CMOS 14.67):
Chaudhuri, Amit. Odysseus Abroad. New York: Alfred A. Knopf, 2015.
———. A Strange and Sublime Address. London: Minerva, 1992.
Traditionally, and in the examples above, each 2-em and 3-em dash literally consists of two and three consecutive dashes, respectively. And that’s how Chicago and most publishers produce those dashes when needed.
But Unicode now defines these dashes as distinct characters: U+2E3A (2-em dash) and U+2E3B (3-em dash). Those were added to the Unicode Standard in 2012 but aren’t in wide use. Not only are they not included in many fonts, but they aren’t all that easy to get from a keyboard. Em dashes, on the other hand, are widely supported and (relatively) easy to insert.
The only drawback to using multiple dashes for 2-em and 3-em dashes is that in some fonts there will be a gap between the consecutive dashes. This can be fixed either by switching fonts or by reducing the letterspacing between dashes.
Chicago-style trivia: The Unicode chart that includes the 2-em and 3-em dashes (“Supplemental Punctuation,” v. 6.1 or later), lists “omission dash” as another name for the 2-em dash, lending support for Chicago’s traditional use in the “Admiral N—— and Lady R——” example above. In common usage, asterisks are often used instead.
A Few More Dashes to Think About
It’s worth mentioning five more dashes, each of which can be found in Unicode’s “General Punctuation” chart (the first four under the heading “Dashes”). Copyeditors following Chicago style won’t normally need to use any of these, but it’s good to be aware of them in case they turn up in one of your documents.
‐ (U+2010, hyphen)
Believe it or not, Unicode defines another form of hyphen that’s simply called a hyphen. The hyphen assigned to U+2010 is identical in appearance to the hyphen-minus, U+002D (i.e., what most of us use as a hyphen), but it has two significant drawbacks. First, it’s not the hyphen you get by pressing the hyphen key. Second, it risks being ignored in a literal search for hyphens (i.e., hyphen-minuses).
So even though U+2010 is apparently preferred by Unicode over U+002D in typeset text (according to version 15.0 of the Unicode Standard, published in September 2022), it’s not what you’ll find in most documents.
‑ (U+2011, non-breaking hyphen [Unicode hyphenates “non-breaking”])
This character is modeled on the hyphen, but unlike an ordinary hyphen (either U+002D or U+2010), it won’t allow a break at the end of a line. MS Word includes a nonbreaking hyphen in its special characters menu, but that one is designed for use in that program only and isn’t the same character. Copyeditors can usually change either variety to an ordinary hyphen (U+002D) in the manuscripts they edit (if any nonbreaking hyphens are needed, they would normally be added after conversion for publication).
‒ (U+2012, figure dash)
The figure dash is designed to be the same width as a numeral (the word figure means numeral in this context), making it useful in tables that include hyphenated numbers that need to align down a column. For that to work, you’ll need to use equally spaced “tabular” figures rather than the proportional kind.
― (U+2015, horizontal bar)
The horizontal bar is notable mainly because the applicable Unicode chart lists “quotation dash” as what Unicode calls an informative alias for that character—in other words, a name that follows an equals sign in the chart and helps to explain how the character is used (like “omission dash” for the 2-em dash). But most publishers use an ordinary em dash for that purpose (see CMOS 6.91). So you can ignore the quotation dash (unless you find one, in which case you can usually change it to an em dash).
⁓ (U+2053, swung dash)
We’ll end with the swung dash, though most of us will never have occasion to use one. You may be familiar with this special kind of dash from printed dictionaries, where it is sometimes seen standing in for a headword within a definition (thereby saving valuable space). Here’s the entry for “dash” (first sense) from the eleventh edition of Merriam-Webster’s Collegiate Dictionary (2003):
Note the angle-bracketed examples. The swung dash looks like a tilde (~, U+007E)—a character that’s available individually from most standard keyboards but is more likely to be seen above the letter n, as in the Spanish word cañón (canyon).
Editors should know how to use hyphens (hyphen-minuses, that is), en dashes, and em dashes correctly. But it can help to know something about minus signs also—and about some of the other variations on the dash—if only to be prepared to troubleshoot any problems and inconsistencies. A dash of knowledge may not be worth much, but a knowledge of dashes will prevent editorial headaches.
† Unicode is the international standard that defines the letters, numbers, and symbols on our screens, assigning to each a unique name and hexadecimal code point. When referred to in text, Unicode code points (or numbers for short) are usually prefaced by U+ (see CMOS 11.2).
‡ You may have noticed that CMOS refers to 2-em and 3-em dashes with numerals. Chicago style would normally call for spelled-out “two” and “three,” but we make an exception in this case (one that goes back to 1906, when the first edition of the Manual was published).
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