space (punctuation)

A space is a punctuation convention for providing interword separation in some scripts, including the Latin, Greek, Cyrillic, and Arabic. Not all languages use spaces between words; the ancient Latin and Greek did not. Spaces were not used to separate words until roughly 600–800 AD. (See interword separation for more on the history.) Traditionally, all CJK languages have no space: modern Chinese and Japanese (except when written with little or no kanji) still do not, but modern Korean uses spaces. For use of spaces after full stops, exclamation marks, and question marks, see discussion in the article Full stop.

Spaces and computers

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 most modern programming languages; with the exception of Haskell, ABC, and Python, which use the amount of whitespace in indentation to indicate the scope of a block (unlike Algol-derived languages, like Pascal, C and Perl, which use braces for that purpose). In word processors and text editors, if a line on a screen is shorter than the width of the screen or window, then the empty space to the right usually does not correspond with space characters in the file: there is simply a code indicating that the next text should be put on a new line. Thus, the size of the file is not made unnecessarily larger. If there are space characters, one usually does not see the difference; text editors and word processors often have an option to make them visible. Also, if there is a space character, the cursor can move there, otherwise usually not.

Spaces and digital typography

In computer programming, the normal space corresponds to Unicode and ASCII character 32, or U+0020. In HTML and XML multiple spaces or new line characters collapse into a single space, unless they are contained in an HTML element such as pre, the xml:space="preserve" XML attribute is used, or CSS defines whitespace="pre" (or pre-line or pre-wrap). The special non-breaking-space   always gives a non-collapsable space character, often used to indent text, though some web authorities discourage using it for that purpose. Other kinds of spaces exist for special uses: for example an em dash can optionally be surrounded with a so-called hair space, Unicode character 8202, or U+200A. This space should be much thinner than a normal space, and is seldom used on its own. It can be written in HTML by using the numeric character entity   or  . Unfortunately, very few user agents are able to render a hair space correctly: in most cases the result is an unwanted symbol or a question mark on the screen (depending on the font).

ormal space versus hair space
Normal space	align=center \| left right
Normal space with em dash	align=center \| left — right
Hair space with em dash	align=center \| left — right
No space with em dash	align=center \| left—right

Unicode defines several space characters for fine typography. Depending on the browser and fonts used to view this table, not all spaces may display properly:

pace characters defined in Unicode
ode	HTML entity	Name	In Block	Display	Description
+0020	not necessary	Space	Basic Latin	align="center"\|] [	Normal space, same as ASCII character 0x20
+00A0		No-Break Space	Latin-1 Supplement	align="center"\|] [	Identical to U+0020, but not a point at which a line may be broken
+1680		Ogham Space Mark	Ogham	align="Center"\|] [	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.
+2002		En Space, or Nut	General Punctuation	align="center"\|] [	Width of one en
+2003		Em Space, or Mutton	General Punctuation	align="center"\|] [	Width of one em
+2004		Three-Per-Em Space, or Thick Space	General Punctuation	align="center"\|] [	One third of an em wide
+2005		Four-Per-Em Space, or Mid Space	General Punctuation	align="center"\|] [	One fourth of an em wide
+2006		Six-Per-Em Space	General Punctuation	align="center"\|] [	One sixth of an em wide
+2007		Figure Space	General Punctuation	align="center"\|] [	In fonts with monospaced digits, equal to the width of one digit
+2008		Punctuation Space	General Punctuation	align="center"\|] [	As wide as the narrow punctuation in a font
+2009		Thin Space	General Punctuation	align="center"\|] [	Approximately one fifth to one sixth of an em wide
+200A		Hair Space	General Punctuation	align="center"\|] [	Thinner than a thin space
+200B		Zero-Width Space	General Punctuation	align="center"\|][	Used to indicate word boundaries to text processing systems when using scripts that do not use explicit spacing; normally not a visible separation, but it may expand in passages that are fully justified
+202F		Narrow No-Break Space	General Punctuation	align="center"\|] [	Similar to U+00A0 No-Break Space
+205F		Medium Mathematical Space	General Punctuation	align="center"\|] [	Used in mathematical formulae
+3000		Ideographic Space	CJK Symbols and Punctuation	align="center"\|]　[	As wide as a CJK character cell

Unicode also provides some visible characters to stand in for space when necessary in the "Control Pictures" block: the Symbol For Space ␠ (U+2420), the Blank Symbol ␢ (U+2422), and the Open Box ␣ (U+2423).

Space (Punctuation)

Spaces and computers

Spaces and digital typography

See also