In writing, a space ( ) is a blank area that separates words, sentences, syllables (in syllabification) and other written or printed glyphs (characters). Conventions for spacing vary among languages, and in some languages the spacing rules are complex.
Contents
Typesetting uses spaces of varying length for specific purposes. The typewriter, on the other hand, can accommodate only a limited number of keys. Most typewriters have only one width of space, obtained by pressing the space bar. Following widespread acceptance of the typewriter, some spacing and other typewriter conventions, which were based on the typewriter's mechanical limitations, have influenced professional typography other designers of printed works.
Computer representation of text eliminates all mechanical and physical limitations. Spaces of various widths, styles, or language characteristics (different space characters) are indicated with unique code points. Whitespace characters include spaces of various width, including all those that professional typesetters employ.
Spaces between words
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 600–800 CE. 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) do not; on the other hand, modern Korean uses spaces.
Runic texts use either an interpunct-like or a colon-like punctuation mark to separate words. There are two Unicode characters dedicated for this: U+16EB ᛫ Runic single punctuation and U+16EC ᛬ Runic multiple punctuation.
Spaces between sentences
Languages with a Latin-derived alphabet have used various methods of sentence spacing since the advent of movable type in the 15th century.
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."
Spaces and unit symbols
The International System of Units (SI) prescribes inserting a space between a number and a unit of measurement and between units in compound units, but never between a prefix and a base unit.
5.0 cm not 5.0cm or 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% (Note: % is not an SI unit, and many style guides do not follow this recommendation)The only exception to this rule is the SI the symbolic notation of angles: degree (e.g., 30°), minute of arc (e.g., 22′), and second of arc (e.g., 8″).