A dash is one of several kinds of punctuation mark. Dashes are similar to hyphens, but differ from them primarily in length, and serve different functions. The most common versions of the dash are the en dash (–) and the em dash (—).
Contents |
There are several forms of dash, of which the most common are:
| glyph | Unicode codepoint[1] | HTML character entity reference | HTML/XML numeric character references | TeX | Alt code (Windows) | Mac OS X key combination | Compose key | |
|---|---|---|---|---|---|---|---|---|
| figure dash | ‒ | U+2012 | none | ‒ or ‒ |
none | |||
| en dash | – | U+2013 | – |
– or – |
-- |
<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">Alt</kbd> + 0150 | <kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">⌥ Opt</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd> | <kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">Compose</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">.</kbd> |
| em dash | — | U+2014 | — |
— or — |
--- |
<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">Alt</kbd> + 0151 | <kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">⌥ Opt</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">⇧ Shift</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd> | <kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">Compose</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd> |
| horizontal bar | ― | U+2015 | none | ― or ― |
none | |||
| swung dash | ⁓ | U+2053 | none | ⁓ or ⁓ |
\~{} |
Less common are the two-em dash (⸺) and three-em dash (⸻). Windows character codes require that <kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">Num Lock</kbd> be on.
The figure dash (‒) is so named because it is the same width as a digit, at least in fonts with digits of equal width. This is true of most fonts, not only monospaced fonts.
The figure dash is used when a dash must be used within numbers. This does not indicate a range, for which the en dash is used; nor does it function as the minus sign, which also uses a separate glyph.
The figure dash is often unavailable; in this case, one may use a hyphen-minus instead. In Unicode, the figure dash is U+2012 (decimal 8210). HTML authors must use the numeric forms ‒ or ‒ to type it unless the file is in Unicode; there is no equivalent character entity. In TeX, the standard fonts have no figure dash; however, the digits normally all have the same width as the en dash, so an en dash can be substituted when using standard TeX fonts.
The en dash, n dash, n-rule, or "nut" (–) is traditionally half the width of an em dash.[2][3] In modern fonts, the length of the en dash is not standardized, and the en dash is often more than half the width of the em dash.[4] The widths of en and em dashes have also been specified as being equal to those of the upper-case letters N and M respectively,[5][6] and at other times to the widths of the lower-case letters.[4][7]
The en dash is commonly used to indicate a closed range of values, meaning a range with clearly defined and non-infinite upper and lower boundaries. This may include ranges such as those between dates, times, or numbers.[8][9][10][11] Examples of this usage may include:
The Guide for the Use of the International System of Units (SI) recommends that the word to be used instead of an en dash when a number range might be misconstrued as subtraction, such as a range of units. For example, "a voltage of 50 V to 100 V" is preferable to using "a voltage of 50–100 V". It is also considered inappropriate to use the en dash in place of the words to or and in phrases that follow the forms from ... to ... and between ... and ....[9][10]
The en dash can also be used to contrast values, or illustrate a relationship between two things.[8][11] Examples of this usage may include:
A "simple" attributive compound is written with a hyphen; at least one authority considers name pairs, where the paired elements carry equal weight, as in the Taft-Hartley Act to be "simple,"[9] while others consider an en dash appropriate in instances such as this[12][13][14] to represent the parallel relationship, as in the McCain–Feingold bill or Bose–Einstein statistics. However, truly compound names are written with a hyphen, thus the Lennard-Jones potential is named after one person, while Bose and Einstein are two people.
In English, the en dash is usually used instead of a hyphen in compound (phrasal) attributives in which one or both elements is itself a compound, especially when the compound element is an open compound, meaning it is not hyphenated itself. This manner of usage may include such examples as:[9][10][15][16]
(the connection between the hospital and the nursing home, not a home connection between the hospital and nursing)
The disambiguating value of the en dash in these patterns was illustrated by Strunk and White in The Elements of Style with the following example: when Chattanooga News and Chattanooga Free Press merged, the joint company was inaptly named Chattanooga News-Free Press, which could be interpreted as meaning that their newspapers were news-free.[17]
An exception to the use of en dashes is made however when prefixing an already hyphenated compound; an en dash is generally avoided as a distraction in this case. Examples of this may include:[17]
As discussed above, the en dash is sometimes recommended instead of a hyphen in compound adjectives where neither part of the adjective modifies the other—that is, when each modifies the noun, as in love–hate relationship. The Chicago Manual of Style (CMOS), however, limits the use of the en dash to two main purposes. First, use it to indicate ranges of time, money, or other amounts, or in certain other cases where it replaces the word to. Second, use it in place of a hyphen in a compound adjective when one of the elements of the adjective is an open compound, or when two or more of its elements are compounds, open or hyphenated.[18] That is, it favors hyphens in instances where some other guides suggest en dashes – the 16th edition explaining that "Chicago's sense of the en dash does not extend to between" to rule out its use in "US-Canadian relations."[18]
En dashes normally do not have spaces around them. An exception is made when avoiding spaces may cause confusion or look odd. For example, compare 12 June – 3 July with 12 June–3 July.[19] However, in rare situations when an en dash is unavailable—such as when using typewriters or character encodings not including the en dash character—it may be substituted with a hyphen-minus with a single space on each side (" - ").
Like em dashes, en dashes can be used instead of colons, or pairs of commas that mark off a nested clause or phrase. They can also be used around parenthetical expressions – such as this one – in place of the em dashes preferred by some publishers, particularly where short columns are used, since em dashes can look awkward at the end of a line. See En dash versus em dash, below. In these situations, en dashes must have a single space on each side.
In TeX, the en dash may normally (depending on the font) be input as a double hyphen-minus (--). On Mac OS X, most keyboard layouts map an en dash to <kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">⌥ Opt</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd>. On Microsoft Windows, an en dash may be entered as Alt+0150 (where the digits are typed on the numeric keypad while holding down the Alt key). In Linux (GTK+ v. 2.10+ applications only, see Unicode input), it is entered by holding down Ctrl+Shift and typing U followed by the Unicode code point above, or using the compose key by pressing the compose key, two hyphens, and a period.
The en dash is sometimes used as a substitute for the minus sign, when the minus sign character is not available, since the en dash is usually the same width as a plus sign. For example, the original 8-bit Macintosh character set had an en dash, useful for minus sign, years before Unicode with a dedicated minus sign was available. The hyphen-minus is usually too narrow to make a typographically acceptable minus sign. But the en dash cannot be used for a minus in programming languages because the syntax usually requires a hyphen-minus; because programming languages are usually set in a fixed-pitch (monospaced) font face, the hyphen-minus looks acceptable there.
The en dash may be used as a bullet mark used at the start of items in a list.
The em dash (—), m dash, m-rule, or "mutton," often demarcates a break of thought or some similar interpolation stronger than the interpolation demarcated by parentheses, such as the following from Nicholson Baker's The Mezzanine:
At that age I once stabbed my best friend, Fred, with a pair of pinking shears in the base of the neck, enraged because he had been given the comprehensive sixty-four-crayon Crayola box—including the gold and silver crayons—and would not let me look closely at the box to see how Crayola had stabilized the built-in crayon sharpener under the tiers of crayons.
It is also used to indicate that a sentence is unfinished because the speaker has been interrupted. For example, the em dash is used in the following way in Joseph Heller's Catch-22:
He was Cain, Ulysses, the Flying Dutchman; he was Lot in Sodom, Deirdre of the Sorrows, Sweeney in the nightingales among trees. He was the miracle ingredient Z-147. He was—
"Crazy!" Clevinger interrupted, shrieking. "That's what you are! Crazy!"
"—immense. I'm a real, slam-bang, honest-to-goodness, three-fisted humdinger. I'm a bona fide supraman."
Similarly, it can be used instead of an ellipsis to indicate aposiopesis, the rhetorical device by which a sentence is stopped short not because of interruption but because the speaker is too emotional to continue, such as Darth Vader's line "I sense something; a presence I've not felt since—" in Star Wars Episode IV: A New Hope.[20]
The term em dash derives from its defined width of one em, which is the length, expressed in points, by which font sizes are typically specified. Thus in 9-point type, an em is 9 points wide, while the em of 24-point type is 24 points wide, and so on (by comparison, the en dash, with its 1-en width, is in most fonts either ½ em wide[21] or the width of an n[22]).
The em dash is used in much the way a colon or a set of parentheses is used; it can show an abrupt change in thought or be used where a full stop (or "period") is too strong and a comma too weak. Em dashes are sometimes used to set off summaries or definitions.[23]
According to most American sources (such as The Chicago Manual of Style) and some British sources (such as The Oxford Guide to Style), an em dash should always be set closed, meaning it should not be surrounded by spaces. But the practice in some parts of the English-speaking world, including the style recommended by The New York Times Manual of Style and Usage, sets it open, separating it from its surrounding words by using spaces or hair spaces (U+200A) when it is being used parenthetically. Some writers, finding the em dash unappealingly long, prefer to use an open-set en dash. This "space, en dash, space" sequence is also the predominant style in German and French typography. See En dash versus em dash below.
In Canada, The Canadian Style [A Guide to Writing and Editing], The Oxford Canadian of Grammar, Spelling & Punctuation, Guide to Canadian English Usage [Second Edition], Editing Canadian English Manual, and the Canadian Oxford Dictionary all specify that an em dash should be set closed when used between words, a word and numeral, or two numerals.
In Australia, the Style manual [For authors, editors and printers, Sixth edition], also specifies that em dashes inserted between words, a word and numeral, or two numerals, should be set closed. A section on the 2-em rule (——) also explains that the 2-em can be used to mark an abrupt break in direct or reported speech, but a space is used before the 2-em if a complete word is missing, while no space is used if part of a word exists before the sudden break. Two examples of this are as follows (note that properly typeset 2-em and 3-em dashes should appear as a single dash, but they may show on this page as several em dashes with spaces in between):
Monospaced fonts that mimic the look of a typewriter have the same width for all characters. Some of these fonts have em and en dashes that more or less fill the monospaced width they have available. For example, the sequence hyphen, en dash, em dash, minus shows as "- – — −" in a monospace font. Typewriters often only have a single hyphen glyph, so it is common to use two monospace hyphens strung together (--) to serve as an em dash.
When an actual em dash is unavailable—as in the ASCII character set—a double ("--") or triple hyphen-minus ("---") is used. In Unicode, the em dash is U+2014 (decimal 8212). In HTML, one may use the numeric forms — or —; there is also the HTML entity —. In TeX, the em dash may normally be input as a triple hyphen-minus (---). On any Mac, most keyboard layouts map an em dash to <kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">⌥ Opt</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">⇧ Shift</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd>. On Microsoft Windows, an em dash may be entered as Alt+0151, where the digits are typed on the numeric keypad while holding the Alt key down. It can also be entered into Microsoft Office applications by using the <kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">Ctrl</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">Alt</kbd>+<kbd class="keyboard-key" style="border: 1px solid; border-color: #ddd #bbb #bbb #ddd; border-bottom-width: 2px; -moz-border-radius: 3px; -webkit-border-radius: 3px; border-radius: 3px; background-color: #f9f9f9; padding: 1px 3px; font-family: inherit; font-size: 0.85em; white-space: nowrap;">-</kbd>. In the X Window System, it may entered using the compose key by pressing the compose key and three hyphens.
Corpus studies indicate that em dashes are more commonly used in Russian than in English.[24]
The en dash is wider than the hyphen but not as wide as the em dash. An em width is defined as the point size of the currently used font, since the M character is not always the width of the point size.[25] In running text, various dash conventions are employed: an em dash—like so—or a spaced em dash — like so — or a spaced en dash – like so – can be seen in contemporary publications.
Various style guides and national varieties of languages prescribe different guidance on dashes. Dashes have been cited as being treated differently in the US and the UK, with the former preferring the use of an em-dash with no additional spacing, and the latter preferring a spaced en-dash.[26] As an example of the US style, The Chicago Manual of Style still recommends unspaced em dashes. Style guides outside of the US tend to diverge from this guidance. For example, the Canadian The Elements of Typographic Style recommends the spaced en dash – like so – and argues that the length and visual magnitude of an em dash "belongs to the padded and corseted aesthetic of Victorian typography."[27] In the United Kingdom, the spaced en dash is the house style for certain major publishers, including the Penguin Group, the Cambridge University Press, and Routledge. But this convention is not universal. The Oxford Guide to Style (2002, section 5.10.10) acknowledges that the spaced en dash is used by "other British publishers", but states that the Oxford University Press—like "most US publishers"—uses the unspaced em dash.
The en dash—always with spaces in running text—and the spaced em dash both have a certain technical advantage over the un-spaced em dash. Most typesetting and word processing expects word spacing to vary to support full justification. Alone among punctuation that marks pauses or logical relations in text, the unspaced em dash disables this for the words it falls between. This can cause uneven spacing in the text, but can be mitigated by the use of thin spaces, hair spaces, or even zero-width spaces on the sides of the em dash. This provides the appearance of an unspaced em dash, but allows the words and dashes to break between lines. The spaced em dash risks introducing excessive separation of words. In full justification, the adjacent spaces may be stretched, and the separation of words further exaggerated. En dashes may also be preferred to em dashes when text is set in narrow columns, such as in newspapers and similar publications, as the en dash is smaller. In such cases, its use is based purely on space considerations and is not necessarily related to other typographical concerns.
U+2015 ― horizontal bar, also known as a quotation dash, is used to introduce quoted text. This is the standard method of printing dialogue in some languages. See the quotation dash section of the Quotation mark, non-English usage article for further details of how it is used. The em dash is equally suitable if the quotation dash is unavailable or is contrary to the house style being used.
There is no support in the standard TeX fonts, but one can use \hbox{---}\kern-.5em--- instead, or just use an em dash.
The Chicago Manual of Style makes no mention of the horizontal bar or the quotation dash but states: "Em dashes are occasionally used instead of quotation marks to set off dialogue (à la writers in some European languages). Each speech starts a new paragraph. No space follows the dash."[28]
U+2053 ⁓ swung dash resembles a lengthened tilde, and is used to separate alternatives or approximates. In dictionaries, it is frequently used to stand in for the term being defined. A dictionary entry providing an example for the term henceforth might employ the swung dash as follows:
There are several similar, related characters:
$\sim$.Several characters resemble dashes but have different meanings and uses. These include:
Typewriters and early computers have traditionally had only a limited character set, often having no key that produces a dash. In consequence, it became common to substitute the nearest available punctuation mark or symbol. Em dashes are often represented in British usage by a single hyphen-minus surrounded by spaces, or in American usage by two hyphen-minuses surrounded by spaces.
Modern computer software typically has support for many more characters, and is usually capable of rendering both the en and em dashes correctly—albeit sometimes with an inconvenient input method. Some software, though, may operate in a more limited mode. Some text editors, for example, are restricted to working with a single 8-bit character encoding, and when unencodable characters are entered—for example by pasting from the clipboard—they are often blindly converted to question marks. Sometimes this happens to em and en dashes, even when the 8-bit encoding supports them, or when an alternative representation using hyphen-minuses is an option.
Any kind of dash can be used directly in an HTML document, but HTML also lets them be entered using character references. The em dash and the en dash are special in that they can be written using character entity references as — and –, respectively.
---), an en dash as two hyphens (--), and a hyphen-minus as one hyphen (-). Mathematical minus is signified as $-$ or \(-\).charmap in the run command box.
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