User:TheSpim

A dash is a punctuation mark that is similar to a hyphen or minus sign but that differs from both of these symbols primarily in length and function. The most common versions of the dash are the en dash (–) and the em dash (—), named for the length of a typeface's lower-case n and upper-case M respectively.

Usage varies both within English and in other languages, but the usual convention in printed English text is:


 * Either version may be used to denote a break in a sentence or to set off parenthetical statements (ideally with intradocument consistency). In this function, en dashes are used with spaces and em dashes are used without them: "[Em dash:] A flock of sparrows—some of them juveniles—alighted and sang.""[En dash:] A flock of sparrows – some of them juveniles – alighted and sang."
 * The en dash (but not the em dash) is also used to indicate spans or differentiation, where it may be considered to replace "and" or "to" (but not "to" in the phrase "from … to …"): "The French and Indian War (1754–1763) was fought in western Pennsylvania and along the present US–Canadian border (Edwards, pp. 81–101)."
 * The em dash (but not the en dash) is also used to set off the sources of quotes:"'In matters of grave importance, style, not sincerity, is the vital thing.'—Oscar Wilde"

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

Less common are the two-em dash (⸺) and three-em dash (⸻), both added to Unicode with version 6.1 as U+2E3A and U+2E3B. Windows character codes require that 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 (e.g. phone number 555‒0199). It 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. In XeLaTeX, one could use  (Linux Libertine font has the figure dash glyph).

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.

In most uses of en dashes, such as when used in indicating ranges, they are closed up to the joined words. It is only when en dashes take the role of em dashes – for example, in setting off parenthetical statements such as this one – that they take spaces around them.

Ranges of values
The en dash is commonly used to indicate a closed range of values—a range with clearly defined and finite upper and lower boundaries—roughly signifying what might otherwise be communicated by the word "through". This may include ranges such as those between dates, times, or numbers. Various style guides restrict this range indication style to only parenthetical or tabular matter, requiring "to" or "through" in running text. Examples of this usage include:

The preference for an en dash instead of a hyphen in ranges is a matter of style preference, not inherent orthographic "correctness"; both are equally "correct", and each is the preferred style in some style guides. For example, APA style uses an en dash in ranges, but AMA style uses a hyphen.

Various style guides (including the Guide for the Use of the International System of Units (SI) and the AMA Manual of Style) recommend that when a number range might be misconstrued as subtraction, the word "to" should be used instead of an en dash. For example, "a voltage of 50 V to 100 V" is preferable to using "a voltage of 50–100 V". Relatedly, in ranges that include negative numbers, "to" is used to avoid ambiguity or awkwardness (for example, "temperatures ranged from −18°C to −34°C"). It is also considered poor style (best avoided) 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 include:
 * Australia beat American Samoa 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

Among writers who use en dashes in these contexts, a distinction is often made between "simple" attributive compounds (written with a hyphen) and other subtypes (written with an en dash); 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, a compound surname is written with a hyphen, thus the Lennard-Jones potential is named after one person, while Bose and Einstein are two people.

The preference for an en dash instead of a hyphen in these coordinate/relationship/connection types of terms is a matter of style preference, not inherent orthographic "correctness"; both are equally "correct", and each is the preferred style in some style guides. For example, the American Heritage Dictionary of the English Language, the AMA Manual of Style, and Dorland's medical reference works use hyphens, not en dashes, in coordinate terms (such as blood-brain barrier), in eponyms (such as Cheyne-Stokes respiration, Kaplan-Meier method, and hundreds of others), and so on.

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 itself hyphenated. This manner of usage may include such examples as:

(the connection between the hospital and the nursing home, not a home connection between the hospital and nursing)
 * The hospital–nursing home connection
 * 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 usually made when prefixing an already hyphenated compound; an en dash is generally avoided as a distraction in this case. Examples of this include:
 * non-English-speaking air traffic controllers
 * semi-labor-intensive industries
 * Proto-Indo-European language
 * The post-MS-DOS era
 * non-government-owned corporations

An en dash can be retained to avoid ambiguity; but whether any ambiguity is plausible is a judgment call. AMA style retains the en dashes in the following examples, but one could argue that some perverseness may be needed to construe the hyphens-only alternative as ambiguous:
 * non–self-governing
 * non–English-language journals
 * non–group-specific blood
 * non–Q-wave myocardial infarction
 * non–brain-injured subjects

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."

In these two uses, 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.

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 TeX, the en dash may normally (depending on the font) be input as a double hyphen-minus. In LaTeX you can also use the macro. On Mac OS X, most keyboard layouts map an en dash to. 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 its Unicode code point, 2013, 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 at the start of each item in a list but a plain hyphen is more commonly used (and even mandatory in formats like Markdown).

Em dash
The em dash, m dash, m-rule, or "mutton" (&mdash;) is longer than an en dash. 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. By comparison, the en dash, with its 1-en width, is in most fonts either a half-em wide or the width of an n.

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 (period) is too strong and a comma too weak. Em dashes are sometimes used to set off summaries or definitions.

It often demarcates a break of thought or form:
 * "I believe I shall—no, I’m going to do it."

It may indicate an interpolation stronger than that demarcated by parentheses, as in 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. In this use, it is sometimes doubled:
 * "But I’m trying to explain that I ——"

In a related use, it may visually indicate the shift between speakers when they overlap in speech. For example, the em dash is used this 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.

A quotation dash may be used to indicate turns in a dialog, in which case each dash starts a paragraph. It replaces other quotation marks, and was preferred by authors such as James Joyce:
 * ―Oh saints above! Miss Douce said, sighed above her jumping rose. I wished I hadn't laughed so much. I feel all wet
 * ―Oh Miss Douce! Miss Kennedy protested. You horrid thing!

The em dash may have the inverse function of a colon:
 * Red, white, and blue—these are the colors of the flag.

Compare:
 * These are the colors of the flag: red, white, and blue.

They may be used to indicate omitted letters in a word reduced to an initial:
 * It was alleged that D— had been threatened with blackmail.

Em dashes are also used to indicate attributions for block quotations, as next.

In Middle Modern English texts and afterward, em dashes were used to add long pauses (as noted by Joseph Robertson's 1785 An Essay On Punctuation): Lord Cardinal! if thou think'st on heaven's bliss, Hold up thy hand, make signal of that hope.— He dies, and makes no sigh!

— Shakespeare, from King Henry

Spacing and substitution
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 and the AP Stylebook, 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 A to Z 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 &mdash;".
 * It was alleged that D&mdash; 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.

When an actual em dash is unavailable—as in the ASCII character set—it has been approximated as a double (--) or triple (---) hyphen-minus. 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. 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. In the X Window System, it may be entered using the compose key by pressing the compose key and three hyphens.

Because early comic book letterers were not aware of the typographic convention of replacing a typewritten double hyphen with an em dash, the double hyphen became traditional in American comics. This practice has continued despite the development of computer lettering.

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 examples of the US style, The Chicago Manual of Style and The Publication Manual of the American Psychological Association recommend unspaced em dashes. Style guides outside the US are more variable. 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 when, as discussed in this section, indicating a parenthesis or pause – and the spaced em dash both have a certain technical advantage over the not 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 not spaced 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 a not spaced 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.

On the other hand, a spaced en dash may be ambiguous when it is also used for ranges, for example in dates or between geographical locations with internal spaces.

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. 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  instead, or just use an em dash.

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:
 * henceforth (adv.) from this time forth; from now on; " ⁓  she will be known as Mrs. Wales"

There are several similar, related characters:
 * (see below)
 * , used in mathematics. In TeX and LaTeX, this character can be expressed using the math mode command.
 * , used in East Asian typography for a variety of purposes, including Japanese punctuation.
 * , used in East Asian typography.

Similar Unicode characters used in specific writing systems

 * is a hyphen from the Mongolian Todo alphabet.
 * is an Ancient Greek textual symbol, usually displayed by a long low line.
 * or are Hangul letters used in Korean to denote the sound.
 * and 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 Japanese chōonpu, is used in Japanese to indicate a long vowel.
 * , the Chinese character for "one", is used in various East Asian languages.
 * looks like a sequence of a hyphen and a full stop.
 * or are Hangul letters used in Korean to denote the sound.
 * and 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 Japanese chōonpu, is used in Japanese to indicate a long vowel.
 * , the Chinese character for "one", is used in various East Asian languages.
 * looks like a sequence of a hyphen and a full stop.

In other languages
In many languages, such as Polish, the em dash in used as an opening quotation mark. There is no matching closing quotation mark; typically a new paragraph will be started, introduced by a dash, for each turn in the dialog.

Corpus studies indicate that em dashes are more commonly used in Russian than in English. In Russian, the em dash is used for the present copula (meaning "am"/"is"/"are"), which is unpronounced in spoken Russian.

In French, em or en dashes can be used as parentheses, except you can choose between using a second dash as a closing parenthesis, or not using one, simply closing your sentence with a period as you would in English. Dashes are, however, much less common than parentheses.

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 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.


 * In GNU/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 OS X using the Australian, British, Canadian, French, German, Irish, Irish Extended, Italian, Pro Italian, Russian, US, US Extended, or Welsh keyboard layout, an en dash can be obtained by typing, while an em dash can be typed with.
 * In TeX, an em dash (—) is typed as three hyphen‐minuses, an en dash (–) as two hyphen‐minuses , and a hyphen (‐) as one hyphen‐minus . 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 includes 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 Alt150 for the en dash or Alt151 for the em dash. The numbers must be typed on the numeric keypad with Num Lock enabled. In addition, the Character Map utility included with MS Windows can be used to copy and paste en and em dash characters into most applications—along with accented letters and other non-English language characters. It can normally be found in the System Tools folder, or the Accessories folder on MS Windows Vista. Character Map can also be opened by typing  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 (on the numeric keypad, with the numeric hyphen usually in the top-right corner), and an en dash can be typed with Ctrl. 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 (as in "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.