[a] Typical uses of dashes are to mark a break in a sentence, to set off an explanatory remark (similar to parenthesis), or to show spans of time or ranges of values.
In the early 17th century, in Okes-printed plays of William Shakespeare, dashes are attested that indicate a thinking pause, interruption, mid-speech realization, or change of subject.
[2][3][1][4] In 1733, in Jonathan Swift's On Poetry, the terms break and dash are attested for ⸺ and — marks:[5] Blot out, correct, insert, refine, Enlarge, diminish, interline; Be mindful, when Invention fails; To scratch your Head, and bite your Nails.
In modern Wit all printed Trash, is Set off with num'rous Breaks⸺and Dashes— Usage varies both within English and within other languages, but the usual conventions for the most common dashes in printed English text are these: Glitter, felt, yarn, and buttons—his kitchen looked as if a clown had exploded.A flock of sparrows—some of them juveniles—alighted and sang.Glitter, felt, yarn, and buttons – his kitchen looked as if a clown had exploded.A flock of sparrows – some of them juveniles – alighted and sang.The French and Indian War (1754–1763) was fought in western Pennsylvania and along the present US–Canada border Seven social sins: politics without principles, wealth without work, pleasure without conscience, knowledge without character, commerce without morality, science without humanity, and worship without sacrifice.The figure dash ‒ (U+2012 ‒ FIGURE DASH) has the same width as a numerical digit.
[15][18] The three main uses of the en dash are: 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" in American English, or "to" in International English.
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 X to Y and between X and Y.
[20][23] Examples of this usage include: 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",[21] while others consider an en dash appropriate in instances such as these[24][25][26] to represent the parallel relationship, as in the McCain–Feingold bill or Bose–Einstein statistics.
When an act of the U.S. Congress is named using the surnames of the senator and representative who sponsored it, the hyphen-minus is used in the short title; thus, the short title of Public Law 111–203 is "The Dodd-Frank Wall Street Reform and Consumer Protection Act", with a hyphen-minus rather than an en dash between "Dodd" and "Frank".
Copyeditors use dictionaries (general, medical, biographical, and geographical) to confirm the eponymity (and thus the styling) for specific terms, given that no one can know them all offhand.
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 so on.
[8] In most uses of en dashes, such as when used in indicating ranges, they are typeset closed up to the adjacent words or numbers.
The en dash is encoded in Unicode as U+2013 (decimal 8211) and represented in HTML by the named character entity –.
However, the en dash cannot be used for a minus sign in programming languages because the syntax usually requires a hyphen-minus.
[42] The em dash is encoded in Unicode as U+2014 (decimal 8212) and represented in HTML by the named character entity —.
It may indicate an interpolation stronger than that demarcated by parentheses, as in the following from Nicholson Baker's The Mezzanine (the degree of difference is subjective).
[46] It replaces other quotation marks and was preferred by authors such as James Joyce:[47] The Walrus and the Carpenter Were walking close at hand; They wept like anything to see Such quantities of sand: "If this were only cleared away," They said, "it would be grand!"
Three em dashes one after another can be used in a footnote, endnote, or another form of bibliographic entry to indicate repetition of the same author's name as that of the previous work,[48] which is similar to the use of id.
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 for printed newspapers 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.
[49][50] The AP Stylebook rejects the use of the open em dash to set off introductory items in lists.
The two-hyphen em dash proxy is perhaps more common, being a widespread convention in the typewriting era.
Various style guides and national varieties of languages prescribe different guidance on dashes.
For example, The Elements of Typographic Style by Canadian typographer Robert Bringhurst 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".
[8] 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.
Alone among punctuation that marks pauses or logical relations in text, the unspaced em dash disables this for the words it falls between.
In such cases, its use is based purely on space considerations and is not necessarily related to other typographical concerns.
A dictionary entry providing an example for the term henceforth might employ the swung dash as follows: In the following table, the "M and 5×" column uses a capital M as a standard comparison to demonstrate the vertical position of different Unicode dash characters.
There is no matching closing quotation mark; typically a new paragraph will be started, introduced by a dash, for each turn in the dialogue.
[citation needed] Corpus studies indicate that em dashes are more commonly used in Russian than in English.
[60] For example: "Llevaba la fidelidad a su maestro —un buen profesor— hasta extremos insospechados."