A dash is one of several kinds of punctuation mark. Dashes appear 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 (—).

Common dashes

There are several forms of dash, of which the most common are:

!	! glyph	! Unicode	! HTML	! HTML/XML	!TeX	Alt Code>Windows Char. Codes	!Mac Keyboard Codes	!Compose key
#Figure dash>figure dash		U+2012 (8210)	none	‒ or ‒	none		''
#En dash>en dash	–	U+2013 (8211)	–	– or –	--	ALT + 0150	Option + -	Compose + - + - + .
#Em dash>em dash	—	U+2014 (8212)	—	— or —	---	ALT + 0151	Shift + Option + -	Compose + - + - + -
#Horizontal bar>horizontal bar	―	U+2015 (8213)	none	― or ―	none	''
#Swung dash>swung dash	⁓	U+2053 (8275)	none	⁓ or ⁓	\~{}	''

Less common are the two-em dash () and three-em dash ().

Windows character codes require the "numlock" key to be on.

Figure dash

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 (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.

En dash

The en dash, n dash, n-rule, or "nut" (–) is traditionally half the width of an em dash. 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. 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, and at other times to the widths of the lower-case letters.

Ranges of values

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. Examples of this usage may include:

June–July 1967

1:00–2:00 p.m.

For ages 3–5

pp. 38–55

President Jimmy Carter (1977–1981)

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 ....

Relationships and connections

The en dash can also be used to contrast values, or illustrate a relationship between two things. Examples of this usage may include:

Kansas beat Missouri 31–0.

Radical–Unionist coalition

Boston–Hartford route

New York–London flight (however, it may be seen that New York to London flight is more appropriate because New York is a single name composed of two valid words; with a dash the phrase is ambiguous and could mean either Flight from New York to London or New flight from York to London)

Mother–daughter relationship

The Supreme Court voted 5–4 to uphold the decision.

The McCain–Feingold bill

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," while others consider an en dash appropriate in instances such as this 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.

Attributive compounds

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:

The hospital–nursing home connection

(the connection between the hospital and the nursing home, not a home connection between the hospital and nursing)

A nursing home–home care policy

Pre–Civil War era

Pulitzer Prize–winning novel

The non–San Francisco part of the world

The post–World War II era (however, a hyphen would be used in post-war era)

Trans–New Guinea languages

The ex–prime minister

The pro-conscription–anti-conscription debate

Public-school–private-school rivalries

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.

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:

non-English-speaking air traffic controllers

semi-labor-intensive industries

Proto-Indo-European language (rarely Proto–Indo-European)

The post-MS-DOS era (rarely post–MS-DOS)

non-government-owned corporations

Differing recommendations

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. 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."

Spacing

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. 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 (" - ").

Parenthetic and other uses at the sentence level

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.

Electronic usage

In Unicode, the en dash is U+2013 (decimal 8211). In HTML, one may use the numeric forms – or –; there is also an HTML entity –. In TeX, the en dash may normally (depending on the font) be input as a double hyphen-minus (--). On a computer running the Mac OS X operating system, most keyboard layouts map an en dash to ⌥-hyphen. 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.

Itemization mark

The en dash may be used as a bullet mark used at the start of items in a list.

Em dash

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.

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 ½ em wide in most fonts.)

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 in lists or definitions, but that is a style guide issue; a colon is often recommended for use instead.

According to most American sources (such as The Chicago Manual of Style) and to 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 (because of the narrow width of newspaper columns), 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):

I distinctly heard him say, 'Go away or I'll ——'.

It was alleged that D—— had been threatened with blackmail.

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 Shift-Option-hyphen. 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 Ctrl-Alt-hyphen combination. On Linux it may 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.

En dash versus em dash

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. 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. 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." 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.

===Horizontal bar===

The horizontal bar or 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.

In Unicode, the quotation dash is U+2015 (decimal 8213). In HTML, it can be input only with the numeric form, ― or ―; there is no equivalent character entity. However, for Web pages one generally uses the em dash. 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 that "em dashes are occasionally used instead of quotation marks (mainly by French writers) to set off dialogue.”

===Swung dash===

The swung dash (⁓ or ~) 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: :henceforth (adv.) from this time forth; from now on; "⁓ she will be known as Mrs. Wales" There are several similar, related characters:

Swung dash ⁓ (U+2053) used in Western typography and lexicography. In HTML this character can be expressed solely in numeric form (⁓ or ⁓).

Tilde operator ∼ (U+223C) used in mathematics. In TeX and LaTeX this character can be expressed using the math mode command ($\sim$).

Wave dash 〜 (U+301C) used in East Asian typography for a variety of purposes, including Japanese punctuation.

Fullwidth tilde ～ (U+FF5E) more commonly, used in East Asian typography.

Similar characters

Several characters resemble dashes but have different meanings and uses. These include:

The hyphen-minus (-), Unicode U+002D, is the standard ASCII hyphen. Sometimes this is used in groups to indicate different types of dash.

The tilde (~), U+007E, is a diacritic mark.

The underscore (_), U+005F, is either a diacritic mark, or a character replacing a standard space.

The macron , U+00AF, is another diacritic mark.

The soft hyphen, U+00AD, is used to indicate where a line may break, as in a compound word or between syllables.

The hyphen , U+2010, is the character that can be used to unambiguously represent a hyphen. The hyphen bullet , U+2043, is a short horizontal line used as a list bullet. The box drawings light horizontal (), U+2500, and several similar characters from the same block.

The minus sign (−), U+2212, −, is an arithmetic operation used in mathematics to represent subtraction or negative numbers.

The wave dash , U+301C, and the wavy dash , U+3030, are wavy lines found in some East Asian character sets. Typographically, they have the width of one CJK character cell (fullwidth form), and follow the direction of the text, being horizontal for horizontal text, and vertical for columnar. They are used as dashes, and occasionally as emphatic variants of the katakana vowel extender mark.

The Armenian hyphen ( ֊ ), U+058A, is a hyphen from the Armenian alphabet.

The Hebrew maqaf , U+05BE, is a hyphen-like character from the Hebrew alphabet. The Mongolian todo hyphen , U+1806, is a hyphen from the Mongolian alphabet. The Hangul Jungseong Eu ( U+3161 or U+1173) is used in Korean to indicate the sound . The Japanese chōonpu , U+30FC, is used in Japanese to indicate a long vowel. The Chinese character for "one" , U+4E00, is used in various East Asian languages.

Rendering dashes on computers

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 manifest directly in an HTML document, but HTML also lets them be entered as character entity references. The entity names for the em dash and the en dash are mdash and ndash; therefore, they can be referenced in HTML as — and –. The equivalent numeric character references are — and –. Nearly all web browsers and operating systems used today are capable of rendering the numeric form, and almost as many correctly display the named form.

In Unicode, the figure dash, en dash, em dash, quotation dash, and swung dash correspond to hexadecimal character codes: U+2012, U+2013, U+2014, U+2015, and U+2053, respectively.

In Linux, under recent versions of GTK+, there are various methods of producing these dashes. For em dashes, one may use the compose key followed by three presses of the hyphen character. For en dashes, one may press the compose key followed by two hyphens and a period. For all dashes, one may press and hold ctrl and shift and then press u (and release them all) after which an underlined 'u' appears. Then, type the Unicode number (i.e., 2015) for the appropriate dash and press enter or the space bar. Also, other keys may be remapped to create dashes.

In Mac OS using the Australian, British, Canadian, German, Irish, Irish Extended, Italian, Pro Italian, Russian, US, US Extended, or Welsh keyboard layout, an en dash can be obtained by typing option-hyphen, while an em dash can be typed with option-shift-hyphen.

In TeX, an em dash is typed as three hyphens (---), an en dash as two hyphens (--), and a hyphen-minus as one hyphen (-). Mathematical minus is signified as "$-$" or "\(-\)".

On Plan 9 systems, an en or em dash may be entered by pressing the Compose key (usually left Alt), followed by typing en or em respectively.

In Microsoft Windows running on a computer whose keyboard has a numeric keypad, an en or em dash may be typed into most text areas by using their respective Alt code by holding down the Alt key and pressing either 0150 or 0151. The numbers must be typed on the numeric keypad with Num Lock enabled. In addition, the Character Map utility included with Windows can be used to copy and paste en and em dash characters,as well as accented letters and other non-English language characters, into most applications. It is usually in the System Tools folder, or the Accessories folder on Windows Vista. Character Map can also be opened by typing charmap in the run command box.

In Microsoft Word running on a computer whose keyboard has a numeric keypad, an em dash can be typed with ctrl + alt + numeric hyphen (on the numeric keypad, usually in the top-right corner), and an en dash can be typed with ctrl + numeric hyphen. This doesn't work with the hyphen key on the main keyboard (usually between "0" and "="), which has completely different functions. With Microsoft Word's default settings, in both Windows and Macintosh versions, an em dash symbol, which is not always a true em dash from the font, is automatically produced by Autocorrect when two unspaced hyphens are entered between words ("word--word"). An en dash, which again is not always a true en dash from the font, is automatically produced when one or two hyphens surrounded by spaces are entered: ("word — word") or ("word -- word"). This feature can be disabled by customizing Autocorrect. Other dashes, spaces, and special characters are possible, found through the Tools menu. Unassigned symbols, such as the true minus sign, can be assigned keyboard shortcuts through the Insert menu. To determine if the true en or em dash from the font are being used rather than a cross-referenced character from the Symbol font, copy and paste samples of the dashes into a text editor such as Windows Notepad. Using the true dash is important if one ever needs to share documents with other users in other applications or operating systems.

In professionally printed documents, a typographer sometimes adds a thin space, hair space, or, rarely, a full inter-word space, on either side of an em dash. In HTML it is possible to generate a thin space using the numeric character reference   or the named entity  , and a hair space using the numeric character reference code  , but current-generation web browsers are not uniformly supportive of this character and may render it incorrectly.

References

External links

Peter K. Sheerin, The trouble with EM 'n EN

Dashes and Hyphens

Colons, Semicolons, and Em-dashes

Commonly confused characters

MediaWiki User's Guide to creating special characters

Category:Punctuation Category:Typography

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