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Blank space

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Blank space

apostrophe ( ’ ' )
brackets ( [ ], ( ), { }, ⟨ ⟩ )
colon ( : )
comma ( , ، 、 )
dash ( , –, —, ― )
ellipsis ( …, ..., . . . )
exclamation mark ( ! )
full stop / period ( . )
hyphen ( )
hyphen-minus ( - )
question mark ( ? )
quotation marks ( ‘ ’, “ ”, ' ', " " )
semicolon ( ; )
slash / stroke / solidus ( /,  ⁄  )
Word dividers
interpunct ( · )
space ( ) ( ) ( )
General typography
ampersand ( & )
asterisk ( * )
at sign ( @ )
backslash ( \ )
bullet ( )
caret ( ^ )
dagger ( †, ‡ )
degree ( ° )
ditto mark ( )
inverted exclamation mark ( ¡ )
inverted question mark ( ¿ )
number sign / pound / hash ( # )
numero sign ( )
obelus ( ÷ )
ordinal indicator ( º, ª )
percent, per mil ( %, ‰ )
plus and minus ( + − )
basis point ( )
pilcrow ( )
prime ( ′, ″, ‴ )
section sign ( § )
tilde ( ~ )
underscore / understrike ( _ )
vertical bar / broken bar / pipe ( ¦, | )
Intellectual property
copyright symbol ( © )
registered trademark ( ® )
service mark ( )
sound recording copyright ( )
trademark ( )
currency (generic) ( ¤ )
currency (specific)
( ฿ ¢ $ ƒ £ ¥ )
Uncommon typography
asterism ( )
hedera ( )
index / fist ( )
interrobang ( )
irony punctuation ( )
lozenge ( )
reference mark ( )
tie ( )
diacritical marks
logic symbols
whitespace characters
non-English quotation style ( « », „ ” )
In other scripts
Chinese punctuation
Hebrew punctuation
Japanese punctuation
Korean punctuation

In writing, a space ( ) is a blank area devoid of content, serving to separate words, letters, numbers, and punctuation. Conventions for interword and intersentence spaces vary among languages, and in some cases the spacing rules are quite complex.

In the classical period, Latin was written with interpuncts (centred dots) as word separators, but that practice was abandoned sometime around AD 200 in favour of scriptio continua, i.e., with the words running together without any word separators. In around AD 600–800, blank spaces started being inserted between words in Latin, and that practice carried over to all languages using the Latin alphabet (e.g. English).

In typesetting, spaces have historically been of multiple lengths with particular space-lengths being used for specific typographic purposes, such as separating words or separating sentences or separating punctuation from words. Following the invention of the typewriter and the subsequent overlap of designer style-preferences and computer-technology limitations, much of this reader-centric variation was lost in normal use.

In computer representation of text, spaces of various sizes, styles, or language characteristics (different space characters) are indicated with unique code points.

Use of the space in natural languages

Spaces between words

Main article: Interword separation

Modern English uses a space to separate words, but not all languages follow this practice. Spaces were not used to separate words in Latin until roughly AD 600–800. Ancient Hebrew and Arabic did use spaces, partly to compensate in clarity for the lack of vowels. Traditionally, all CJK languages have no spaces: modern Chinese and Japanese (except when written with little or no kanji) still do not, but modern Korean uses spaces.

Spaces between sentences

Main article: Sentence spacing

Languages with a Latin-derived alphabet have used multiple methods of sentence spacing since the advent of movable type in the 15th century.

  • One space (French Spacing). This is a common convention in most countries that use the ISO basic Latin alphabet for published and final written work, as well as digital (World Wide Web) media.[1] Web browsers usually do not differentiate between single and multiple spaces in source code when displaying text, unless text is given a "white-space" CSS attribute. Without this being set, collapsing strings of spaces to a single space allows HTML source code to be spaced in a more readable way, at the expense of control over spacing of the rendered page.[2]
  • Double space (English Spacing). It is sometimes claimed that this convention stems from the use of the monospaced font on typewriters.[3] However, instructions to use more spacing between sentences than words date back centuries, and two spaces on a typewriter was the closest approximation to typesetter's previous rules aimed at improving readability.[4] The practice was carried on by typesetters and typists until the Second World War, after which it was gradually replaced by a single space convention in published print, where space is sometimes at a premium.[5][6][7][8][9][10][11][12][13][14][15]
  • One widened space, typically one-and-a-third to slightly less than two times as wide as a word space. This spacing has been seen in early typesetting practices (prior to the nineteenth century). It has also been used in other non-typewriter typesetting systems such as the Linotype machine[16] and the TeX system.[17] Modern computer-based digital fonts can adjust the spacing after terminal punctuation as well, creating a space slightly wider than a standard word space.[18]
  • No space. According to Lynne Truss, "young people" today using digital media "are now accustomed to following a full stop with a lower-case letter and no space".[19]

There has been some controversy regarding the proper amount of sentence spacing in typeset material. The Elements of Typographic Style states that only a single word space is required for sentence spacing since "Larger spaces...are themselves punctuation."[20]

Spaces and unit symbols

The International System of Units, or SI,[21] and the style guide on the English-language World Heritage Encyclopedia[22] recommend a (non-breakable) space between a number and its units, as well as between units in the case of compound units, but never between the prefix of an SI unit and the unit.

5.0 cm not 5.0 c m
45 kg not 45kg or 45 k g
32 °C not 32°C or 32° C
20 kN m not 20 kNm or 20 k Nm
50 % not 50% (World Heritage Encyclopedia does not follow this SI recommendation.)

The only exceptions to this rule in the SI are for the symbols for degree, minute, and second for plane angle, as in 30° 22′ 8″.

For the sake of clarity, a hyphen may be inserted between a numeral and a symbol used adjectivally:

35-mm film
60-W bulb

However, some other style guides, including World Heritage Encyclopedia's, deprecate hyphenation in these cases. The SI allows a hyphen between the numeral and the unit only when the name of the unit is spelled out, as 35-millimetre film.[21]

Space characters and digital typography

Variable-width general-purpose space

In computer character encodings, there is a normal general-purpose space (Unicode character U+0020; 32 decimal) whose width will vary according to the design of the typeface. Typical values range from 1/5 em to 1/3 em (in digital typography an em is equal to the nominal size of the font, so for a 10-point font the space will probably be between 2 and 3.3 points). Sophisticated fonts may have differently sized spaces for bold, italic, and small-caps faces, and often compositors will manually adjust the width of the space depending on the size and prominence of the text.

In addition to this general-purpose space, it is possible to encode a space of a specific width. See the table below for a complete list.

In monospaced proofreading copy, only em- and en-spaces are represented using this character (which is called an em-quad or an en-quad), while other types of spaces are represented with a number sign (see Number sign#Space in particular).

Breaking and non-breaking spaces

By default, computer programs usually assume that, in flowing text, a line break may as necessary be inserted at the position of a space. The non-breaking space, U+00A0 (160 decimal), is intended to render the same as a normal space but prevents line-wrapping at that position.

Hair spaces around dashes

In American typography, both en dashes and em dashes are set continuous with the text (as illustrated by use in The Chicago Manual of Style, 6.80, 6.83–86). However, an em dash can optionally be surrounded with a so-called hair space, U+200A (8202 decimal), or thin space, U+2009 (8201 decimal). The thin space can be written in HTML by using the named entity and the hair space can be written using numeric character reference or . This space should be much thinner than a normal space, and is seldom used on its own.

Normal space versus hair space
(as rendered by your browser)
Normal space left right
Normal space with em dash left — right
Thin space with em dash left — right
Hair space with em dash left — right
No space with em dash left—right

Spaces in Unicode

Unicode defines[23] several space characters with specific semantics and rendering characteristics, as shown in the table below. Depending on the browser and fonts used to view this table, not all spaces may display properly:

Spacing characters in Unicode
Code Dec Break in URL HTML Name Block Display
U+0020 32 Yes No Space Basic Latin ] [
Normal space, same as ASCII character 0x20
U+00A0 160 No No   No-Break Space Latin-1 Supplement ] [
Identical to U+0020, but not a point at which a line may be broken
U+1680 5760 Yes Yes Ogham Space Mark Ogham ] [
Used for interword separation in Ogham text. Normally a vertical line in vertical text or a horizontal line in horizontal text, but may also be a blank space in "stemless" fonts. Requires an Ogham font.
U+180E 6158 Yes Yes Mongolian Vowel Separator (MVS) Mongolian ]᠎[
A narrow space character (not to be confused with "thin space", below) used in Mongolian to cause the final two characters of a word to take on different shapes.[24]
U+2000 8192 Yes No[lower-alpha 1] En quad General Punctuation ] [
Width of one en. U+2002 is canonically equivalent to this character; U+2002 is preferred.
U+2001 8193 Yes No[lower-alpha 1] Em quad
Mutton quad
General Punctuation ] [
Width of one em. U+2003 is canonically equivalent to this character; U+2003 is preferred.
U+2002 8194 Yes No[lower-alpha 1] En Space
General Punctuation ] [
Width of one en. U+2000 En Quad is canonically equivalent to this character; U+2002 is preferred.
U+2003 8195 Yes No[lower-alpha 1] Em Space
General Punctuation ] [
Width of one em. U+2001 Em Quad is canonically equivalent to this character; U+2003 is preferred.
U+2004 8196 Yes No[lower-alpha 1] Three-Per-Em Space
Thick Space
General Punctuation ] [
One third of an em wide
U+2005 8197 Yes No[lower-alpha 1] Four-Per-Em Space
Mid Space
General Punctuation ] [
One fourth of an em wide
U+2006 8198 Yes No[lower-alpha 1] Six-Per-Em Space General Punctuation ] [
One sixth of an em wide. In computer typography sometimes equated to U+2009.
U+2007 8199 No No[lower-alpha 1] Figure Space General Punctuation ] [
In fonts with monospaced digits, equal to the width of one digit.
U+2008 8200 Yes No[lower-alpha 1] Punctuation Space General Punctuation ] [
As wide as the narrow punctuation in a font, i.e. the advance width of the period or comma.[25]
U+2009 8201 Yes No[lower-alpha 1] Thin Space General Punctuation ] [
One fifth (sometimes one sixth) of an em wide. Recommended for use as a thousands separator for measures made with SI units. Unlike U+2002 to U+2008, its width may get adjusted in typesetting.[26]
U+200A 8202 Yes No[lower-alpha 1] Hair Space General Punctuation ] [
Thinner than a thin space
U+200B 8203 Yes No[lower-alpha 1] Zero Width Space (ZWSP) General Punctuation ]​[
Used to indicate word boundaries to text processing systems when using scripts that do not use explicit spacing. It is similar to the soft hyphen, with the difference that the latter is used to indicate syllable boundaries, and should display a visible hyphen when the line breaks at it.
U+200C 8204 Yes Yes Zero Width Non Joiner (ZWNJ) General Punctuation ]‌[
When placed between two characters that would otherwise be connected, a ZWNJ causes them to be printed in their final and initial forms, respectively.
U+200D 8205 Yes Yes Zero Width Joiner (ZWJ) General Punctuation ]‍[
When placed between two characters that would otherwise not be connected, a ZWJ causes them to be printed in their connected forms.
U+202F 8239 No No[lower-alpha 1] Narrow No-Break Space General Punctuation ] [
Similar in function to U+00A0 No-Break Space. Introduced in Unicode 3.0 for Mongolian,[27] to separate a suffix from the word stem without indicating a word boundary. When used with Mongolian, its width is usually one third of the normal space; in other context, its width resembles that of the Thin Space (U+2009) at least with some fonts. This char is also used in French before ";?!»" chars and after "«".
U+205F 8287 Yes No[lower-alpha 1] Medium Mathematical Space (MMSP) General Punctuation ] [
Used in mathematical formulae. Four-eighteenths of an em.[28] In mathematical typography, the widths of spaces are usually given in integral multiples of an eighteenth of an em, and 4/18 em may be used in several situations, for example between the a and the + and between the + and the b in the expression a + b.[29]
U+2060 8288 No Yes Word Joiner (WJ) General Punctuation ]⁠[
Identical to U+200B, but not a point at which a line may be broken. Introduced in Unicode 3.2 to replace the deprecated "zero width no-break space" function of the U+FEFF character.
U+3000 12288 Yes No[lower-alpha 1] Ideographic Space (used for example as tai tou) CJK Symbols and Punctuation ] [
As wide as a CJK character cell (fullwidth)
U+FEFF 65279 No Yes Zero Width No-Break Space
= Byte Order Mark (BOM)
Arabic Presentation Forms-B ][
Used primarily as a Byte Order Mark. Use as an indication of non-breaking is deprecated as of Unicode 3.2, see U+2060 instead.

Unicode also provides some visible characters to stand in for space when necessary:

Space illustrating characters (visible) in Unicode
Code Dec Name Block Display Description
U+00B7 183 Middle dot Basic Latin · interpunct, used in text processors. HTML also: ·
U+237D 9085 Shouldered open box Miscellaneous Technical used for NBSP
U+2420 9248 Symbol for space Control Pictures
U+2422 9250 Blank symbol Control Pictures
U+2423 9251 Open box Control Pictures

Use of the space in computing

In programming language syntax, spaces are frequently used to explicitly separate tokens. Aside from this use, spaces and other whitespace characters are usually ignored by modern programming languages. Exceptions are Haskell, occam, ABC, and Python, which use the amount of whitespace in indentation to indicate the bounds of a block, and a whimsical language called Whitespace, where whitespace is the only meaningful syntactical element.

In commands processed by command processors, e.g. in scripts and typed in, the space character can cause problems as it has two possible functions: as part of a command or parameter, or as a parameter or name separator. Ambiguity can be prevented either by prohibiting embedded spaces, or by enclosing a name with embedded spaces between quote characters.

Text editors, word processors, and desktop publishing software differ in how they represent whitespace on the screen, and how they represent spaces at the ends of lines longer than the screen or column width. In some cases, spaces are shown simply as blank space; in other cases they may be represented by an interpunct or other symbols. Many different characters (described below) could be used to produce spaces, and non-character functions (such as margins and tab settings) can also affect whitespace.

Hard spaces (contrasted with "soft spaces") may be defined by some word processors and operating systems as either a non-breaking space, a non-combining/non-expanding space, or some other special character.

Space characters in markup languages

Generalised markup languages, such as SGML, do not treat space characters differently from other characters.

However, special-purpose markup languages may. In particular, web markup languages such as XML and HTML treat whitespace characters specially, including space characters, for programmers' convenience. One or more space characters read by conforming Display-time processors of those markup languages are collapsed to 0 or 1 space, depending on their semantic context. For example, double (or more) spaces within text are collapsed to a single space, and spaces which appear on either side of the "=" that separates an attribute name from its value have no effect on the interpretation of the document. Element end tags can contain trailing spaces, and empty-element tags in XML can contain spaces before the "/>".

In XML attribute values, sequences of whitespace characters are treated as a single space when the document is read by a parser.[32] Whitespace in XML element content is not changed in this way by the parser, but an application receiving information from the parser may choose to apply similar rules to element content. An XML document author can use the xml:space="preserve" attribute on an element to instruct the parser to discourage the downstream application from altering whitespace in that element's content.

In most HTML elements, a sequence of whitespace characters is treated as a single inter-word separator, which may manifest as a single space character when rendering text in a language that normally inserts such space between words.[33] Conforming HTML renderers are required to apply a more literal treatment of whitespace within a few prescribed elements, such as the pre tag and any element for which CSS has been used to apply pre-like whitespace processing. In such elements, space characters will not be "collapsed" into inter-word separators.

In both XML and HTML, the non-breaking space character, along with other non-"standard" spaces, is not treated as collapsible "whitespace", so it is not subject to the rules above.

See also


Further reading

External links

  • Unicode spaces, by Jukka "Yucca" Korpela
  • Commonly confused characters
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