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A dash is a punctuation mark, and is not to be confused with
the hyphen, which has quite different uses.
Common dashes
Several forms of dashes exist, of which the most common are:
- The figure dash (‒)
- The minus sign (−)
- The en dash (–)
- The em dash (—)
- The quotation dash (―).
Figure dash
The figure dash (‒) is so named because it is the same width as a digit (although this may only be true
in monospace fonts). 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
‒ or ‒ to type it; there is no equivalent HTML entity.
Minus sign
The minus sign (−) is an arithmetic operator. This
character is used only in mathematical formulas and equations, and it is usually designed to be the same length and height as the
plus and equals signs. In most fonts these are usually monospaced along with the numbers for ease when being used in tabular
formats. Use the HTML entity − to type it, or the numeric forms − or
−.
En dash
The en dash (–) is one en in width: the width of the capital N in any particular font. 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).
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 – or the numeric forms
– or –, in either case without spaces around it.
Em dash
The em dash (—) is defined as one em in width: the width of the capital M in any particular font. 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 — or
the numeric forms — or —.
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, in Wikipedia use the em dash instead. It can be typed only with the numeric form, ― 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. In mathematics, it is used to show
similarity, equivalence, or asymptotic relations.
Summary
To summarize the above:
- To write a number with a dash in it, use the figure dash ‒ (‒)
- For mathematical operations, use the minus sign − (−)
- For a closed range, use an en dash – (–)
- For a compound adjective with a space, use an en dash – (–)
- For an open range, use an em dash — (—)
- For parenthetical statements, use an em dash — (—)
- To introduce a quote, use a quotation dash ― (―) only when you are certain this will work, otherwise use an
em dash — (—)
- To separate alternatives, or to replace a defined term in an example of usage within a definition, use a swung dash ⁓
(⁓)
See also
Wikipedia:Manual of Style#Dashes
Other dashes and dash-like characters
- The hyphen-minus ( - ) is the standard ASCII hyphen. It looks like a dash, but should never be used as such outside of ASCII.
- The tilde ( ~ ) is a diacritic mark.
- The underscore ( _ ) is either a diacritic mark, or a
character replacing a standard space.
- The Macron ( ¯ ) is another diacritic mark.
- The soft hyphen ( ) is a hyphen which
should only appear at a page break.
- The Armenian hyphen ( ֊ ) is a hyphen from the Armenian alphabet.
- The Mongolian todo hyphen ( ᠆ ) is a hyphen from the Mongolian alphabet.
- The hyphen ( ‐ ) is a character which, unlike the ASCII
hyphen, always represents a hyphen.
- The hyphen bullet ( ⁃ ), Unicode U+2043, is a short horizontal line used as a list bullet.
- The wave dash ( 〜 ), Unicode 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 —
and –. The equivalent HTML numeric character entity 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 characters U+2012, U+2013, U+2014,
U+2015, and U+2053, respectively.
Under Mac OS X, an em dash can be obtained in any application by typing
shift-option-dash. An en dash can be obtained with option-dash.
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, 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"). More directly, 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. 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 to shortcuts (such as ctrl+shift+numeric hyphen) through Insert
-> Symbol... -> (select desired symbol) -> Shortcut key...
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: meta:MediaWiki User's Guide: Creating special
characters.
External links
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