Wikipedia:Hyphens and dashes

This essay introduces the basics of hyphens, minus signs, en dashes, and em dashes in one easy lesson.

There are at least eight different horizontal dash-like characters of varying lengths defined in Unicode. Wikipedia uses four: the hyphen (sometimes called the hyphen-minus), the minus sign, the en dash, and the em dash.

Hyphen (" ", MOS:HYPHEN) (actually the hyphen-minus character in ASCII or Unicode character sets) are used in many ways on Wikipedia. They are the only short, horizontal dash-like character available as a separate key on most keyboards. They are used:
 * in names, such as "Julia Louis-Dreyfus" and "Sainte-Ode",
 * in compound modifiers, as in "hard-boiled egg", "small-appliance industry", and "real-valued function",
 * for prefixes and suffixes, such as "mid-Atlantic" and "shell-like",
 * when prefixing a capitalized word, such as "un-Christian",
 * to avoid double vowels, such as "semi-independent"
 * when writing out fractions like "one-third" or "three-fifths"

In some styles, minus signs are represented using an en dash instead of a minus sign or a hyphen. This is not done in Wikipedia. In math formulas a hyphen-minus codes for a minus sign, but in text  produces the minus sign (see below).

En dash (" ", MOS:ENDASH) are slightly longer than hyphens. They are used: Spaced en dashes are also used to set aside a phrase – like this – in a sentence; when this is done, it is preferred that a non-breaking space be used before the en dash and a normal one after it:.
 * in date ranges, such as 1849–1863,
 * to join two names in a phrase, such as the Michelson–Morley experiment,
 * in multi-part prefixes, such as "post–World War II", although for those, either a hyphen or an en dash can be used; British publications use hyphens, and American publications use en dashes.

Em dash (" ", MOS:EMDASH) are even longer and are used solely to set aside a phrase—like this—in a sentence.

Em dashes and en dashes, when used to set off parentheticals, are, along with parentheses (round brackets) and commas; the principal differences are that parentheses are used to offset text of an optional or "aside" nature, commas are used to offset text that flows as an integral part of the sentence, and dashes are used to offset text in an emphasized manner.

Minus sign (" ", Manual of Style/Mathematics) are available for negative numbers such as −4 but can cause difficulties in sorts and searches.

Entry of these characters
Since 2014, Wikipedia automatically includes the en dash, em dash, and minus characters in the "Insert" tools below the text-entry field when in editing mode. For those who have turned this feature off in their user preferences, the information below may be used to help generate these characters.

Hyphens (" ") can be used for initial entry of an em dash, en dash, or minus sign, which will be replaced with a more precise form may be done by other subsequent editors. Disrupting Wikipedia to constantly complain about the consensus for the more precise forms can be annoying.

Many computer devices have special key chords (combinations of keys) which can be pressed together to enter various dash characters.
 * On computers with Windows XP or Windows 7 (or similar), digits on the numeric keypad can be pressed with the Alt key held then released:
 * Numeric keypad: Alt150 for en dash "–" or Alt151 for em dash "—".
 * On computers using Apple keyboards (Mac OS), the Option key can be used with hyphen key:
 * Option key: Opt for en dash "–" or Shift for em dash "—".
 * On iOS Devices, tap and hold (long press) the - on-screen key to display choices for the en dash "–" and em dash "—".

The four hyphen/dash-like characters used in Wikipedia are:


 * 1) - is a hyphen-minus (ASCII 2D, Unicode 002D), normally used as a hyphen, or in math expressions as a minus sign
 * 2) – is an en dash (Unicode 2013). This can also be entered from the Special characters: Symbols bar above the text-entry field; it's between the m³ and —
 * 3) &mdash; is an em dash (Unicode 2014). This can also be entered from the Special characters: Symbols bar; it's between the – and …
 * 4) − is a minus (Unicode 2212). This can also be entered from the Special characters: Symbols bar; it's between the ± and ×

These characters may also be generated with character entity reference codes inserted into wikitext:

The hyphen-minus can also be generated this way, but this is rarely necessary except for technical reasons in template development:
 * En dash:  a.k.a.   a.k.a.
 * Em dash:  a.k.a.   a.k.a.
 * Minus:  a.k.a.   a.k.a.
 * Hyphen minus:  a.k.a.