Dash

Punctuation marks

apostrophe (' )
parentheses ( ( ) ),
brackets ( [ ] ); ( { } ); ( < > )
colon ( : )
comma ( , )
dash ( ); ( ); ( ); ( )
ellipsis ( ) ( ... )
exclamation mark ( ! ); ( ¡ ! )
full stop/period ( . )
hyphen ( - ); ( )
interrobang ( )
question mark ( ? ); ( ¿ ? )
quotation marks ( ‘ ’ ); ( “ ” );
    ( ‚ ’ ); ( „ ” ); ( ‚ ‘ ); ( „ “ );
    ( ‹ › ); ( « » ); ( › ‹ ); ( » « );
    ( 「 」 ); ( 『 』 )
semicolon ( ; )
slash ( / ) and backslash ( \ )
space (   ) and interpunct ( · )

ampersand ( & )
asterisk ( * ) and asterism ( )
dagger ( † ‡)
bullet ( , more )
commercial at ( @ )
number sign ( # )
prime ( ′ ) and double prime (″)
tilde ( ~ )
underscore ( _ )
vertical bar / pipe ( | )

A dash is a punctuation mark, and is not to be confused with the hyphen, which has quite different uses.

Contents

Common dashes

Several forms of dashes exist, of which the most common are:

  glyph Unicode HTML
figure dash U+2012
en dash U+2013 &ndash;
em dash U+2014 &mdash;
quotation dash U+2015
swung dash U+2053


Figure dash

The figure dash (‒) is so named because it is the same width as a digit—in fonts with digits of equal width. This dash is used when a dash must be used within numbers, for example with telephone numbers: 634‒5789. Note that this does not indicate a range (use an en dash instead), or function as the minus sign (which has its own glyph). Use the numeric forms &#8210; or &#x2012; to type it; there is no equivalent HTML entity.

En dash

The en dash (–) is one en in width. The en dash is by definition exactly half the width of an em dash.

It is used to indicate a closed range, or a connection between two things of almost any kind: numbers, people, places, etc.. Examples:

  • June–July 1967
  • 1:00–2:00 p.m.
  • For ages 3–5
  • pp. 38–55.
  • New York–London flight

You would also use an en dash when you have a compound adjective, one part of which consists of two words or a hyphenated word:

  • pre–World War II period
  • high-priority–high-pressure tasks (tasks which are both high-priority and high-pressure).

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.

An en dash correctly does not have spaces around it; however, when an actual en dash is unavailable, use a dash with single spaces (" - ") to distinguish from a hyphen; or (better) use the HTML entity &ndash; or the numeric forms &#8211; or &#x2013;, in either case without spaces around it.

Em dash

The em dash (—) is defined as one em in width. By definition the em dash is twice as wide as the en dash in any particular font.

It indicates a sudden break in thought—a parenthetical statement like this one—or an open range ("John Doe, 1987—"). The em dash is used in much the way a colon or set of parentheses is used: it can show an abrupt change in thought or be used where a period is too strong and a comma too weak.

In North American usage—and also in old British usage—an em dash is never surrounded by spaces. In contrast, the modern practice in Europe and Australasia — and, indeed, many other parts of the English-speaking world — is to separate the dash from its surrounding words when used parenthetically, by using spaces or hair spaces (U+200A). (Note that hair spaces may not display in most user agents.) Some writers eschew the use of the em dash – instead, they replace it with the shorter en dash – which is then also surrounded by spaces or hair spaces; this "space, en dash, space" sequence is also the predominant style in German typography.

When an actual em dash is unavailable, a doubledash ("--") can be used to distinguish from a hyphen in American English. However, this has never been accepted in other variants, such as Commonwealth English, and the same method as when using an en dash could be used instead (namely, " - "). A better use, if possible, would be to use the HTML entity &mdash; or the numeric forms &#8212; or &#x2014;.

Em dashes are sometimes used in lists of definitions, but this is not considered correct usage: a colon should be used instead.

En dash versus Em dash

Some people prefer to use an en dash instead of an em dash for parenthetical statements. A spaced en dash is commonly used for this purpose in British publications, whereas in the USA the tendency is to use the unspaced em dash. However, it is sometimes argued that using an en dash here can lead to confusion, on the grounds that the dashes have different semantic meanings.

Quotation dash

The quotation dash or horizontal bar (―) is used to introduce quoted text. In most fonts it is rendered identically to the em dash, which can also be used. Since browser support for it is nearly non-existent and Unicode itself equates use, for web pages one should generally use the em dash instead. It can be typed only with the numeric form, &#x2015; there is no equivalent HTML entity.

Swung dash

The swung dash (⁓) resembles a lengthened tilde, and is used to separate alternatives. In dictionaries, it is frequently used to stand in for the defined term in example text. It can be typed only with the numeric form, &#x2053; there is no equivalent HTML entity.

Summary

To summarize the above:

  • To write a number with a dash in it, use the figure dash ‒ (&#8210;)
  • For a closed range, use an en dash – (&ndash;)
  • For a compound adjective with a space, use an en dash – (&ndash;)
  • For an open range, use an em dash — (&mdash;)
  • For parenthetical statements, use an em dash — (&mdash;)
  • To introduce a quote, use a quotation dash ― (&#8213;) only when you are certain this will work, otherwise use an em dash — (&mdash;)
  • To separate alternatives, or to replace a defined term in an example of usage within a definition, use a swung dash ⁓ (&#8275;)

Other dash-like characters

The are several characters which resemble dashes but have different meanings and uses. These include:

  • The hyphen-minus ( - ), Unicode U+002D, is the standard ASCII hyphen. It looks like a dash, but should never be used as such outside of ASCII.
  • 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 a hyphen which should only appear at a line break.
  • The Armenian hyphen ( ֊ ), U+058A, is a hyphen from the Armenian alphabet.
  • The Mongolian todo hyphen ( ᠆ ), U+1806, is a hyphen from the Mongolian alphabet.
  • The hyphen ( ‐ ), U+2010, is a character which, unlike the ASCII hyphen, always represents a hyphen.
  • The hyphen bullet ( ⁃ ), U+2043, is a short horizontal line used as a list bullet.
  • The minus sign ( − ), U+2212, is an arithmetic operator used in mathematics to represent subtraction or negative numbers.
  • The wave dash ( 〜 ), U+301C, and the wavy dash ( 〰 ), U+3030, are wavy horizontal lines found in some east asian character sets, and included in Unicode for backward-compatibility.

Rendering dashes on computers

Typewriters and computers have traditionally had only a limited character set, often having no key with which to produce a dash. In consequence, it became common to substitute the nearest incorrect punctuation mark or symbol. Em dashes are often represented by a pair of spaces surrounding a single minus sign (typical British usage) or by a pair of spaces surrounding two minus signs (mostly in the United States).

Modern computer software, however, typically has a much expanded character set and is usually perfectly capable of rendering both the en and em dashes correctly—albeit with a little inconvenience.

The HTML entity names for the em dash and the en dash are &mdash; and &ndash;. The equivalent HTML numeric character entity references are &#8212; and &#8211;. 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 characters U+2012, U+2013, U+2014, U+2015, and U+2053, respectively.

On an Apple Macintosh using the U.S. 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 as one hyphen ("-").

In Microsoft Word for Windows and Macintosh, an em dash will be produced by Autocorrect when two hyphens are entered between words ("word--word"). An en dash is produced by two hyphens surrounded by spaces ("word -- word"). Other dashes, spaces, and special characters are possible, found through Tools -> Customize... -> Keyboard... -> Common Symbols. Unassigned symbols (such as the true minus sign) can be assigned keyboard shortcuts through Insert -> Symbol... -> (select desired symbol) -> Shortcut key...

In Word for Windows, 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. Note that it will not work with the hyphen key on the main keyboard (usually between "0" and "="), which has completely different functions associated with these commands.

In professionally printed documents, the typographer sometimes adds a hair space on either side of an em dash (a refinement that is not practicable in electronic form given the limitations of current-generation web browsers) or even a full space, though this last is uncommon.

See also

External links



ja:ダッシュ (記号)

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