The zero-width space (ZWSP) is a non-printing character used in computerized typesetting to indicate where the word boundaries are, without actually displaying a visible space in the rendered text. This enables text-processing systems for scripts that do not use explicit spacing to recognize where word boundaries are for the purpose of handling line breaks appropriately. Zero-width space is unicode character U+200B, and is located in the unicode General Punctuation block, and can be represented by numeric character references ​ or ​.

The zero-width space marks a potential line break without hyphenation. Its semantics and HTML implementation are similar to the soft hyphen, but soft hyphens display a hyphen character at the point where the line is broken.

The zero-width space can be used to mark word breaks in languages without visible space between words, such as Thai, Myanmar, Khmer, and Japanese.^[1]

In justified text, the rendering engine may add inter-character spacing, also known as letter spacing, between letters separated by a zero-width space, unlike around fixed-width spaces.^[1]

To show the effect of the zero-width space in text, the following words have been separated with zero-width spaces:

Lorem​Ipsum​Dolor​Sit​Amet​Consectetur​Adipiscing​Elit​Sed​Do​Eiusmod​Tempor​Incididunt​Ut​Labore​Et​Dolore​Magna​Aliqua​Ut​Enim​Ad​Minim​Veniam​Quis​Nostrud​Exercitation​Ullamco​Laboris​Nisi​Ut​Aliquip​Ex​Ea​Commodo​Consequat​Duis​Aute​Irure​Dolor​In​Reprehenderit​In​Voluptate​Velit​Esse​Cillum​Dolore​Eu​Fugiat​Nulla​Pariatur​Excepteur​Sint​Occaecat​Cupidatat​Non​Proident​Sunt​In​Culpa​Qui​Officia​Deserunt​Mollit​Anim​Id​Est​Laborum

And the following words have not been separated with these spaces:

LoremIpsumDolorSitAmetConsecteturAdipiscingElitSedDoEiusmodTemporIncididuntUtLaboreEtDoloreMagnaAliquaUtEnimAdMinimVeniamQuisNostrudExercitationUllamcoLaborisNisiUtAliquipExEaCommodoConsequatDuisAuteIrureDolorInReprehenderitInVoluptateVelitEsseCillumDoloreEuFugiatNullaPariaturExcepteurSintOccaecatCupidatatNonProidentSuntInCulpaQuiOfficiaDeseruntMollitAnimIdEstLaborum

The first text only breaks at word boundaries, while the second text will not be broken at all. Resizing the browser window will re-break the text accordingly.

In HTML pages, the HTML element <wbr> functions as a zero-width space. In Internet Explorer 6, the zero-width space was not supported in some fonts.^[2]

ICANN rules prohibit domain names from containing non-displayed characters, including the zero-width space, and most browsers prohibit their use within domain names because they can be used to create a homograph attack, where a malicious URL is visually indistinguishable from a legitimate one.^[3][4]

The zero-width space character is encoded in Unicode as U+200B ZERO WIDTH SPACE,^[5] and input in HTML as ​, ​ or ​. Contrary to what their names suggest, the character entities ​, ​, ​, and ​ also refer to the zero-width space.^[6]

The TeX representation is \hskip0pt; the LaTeX representation is \hspace{0pt};^[7] and the groff representation is \:.^[8]

• Hair space
• Whitespace character – including a table comparing various space-like characters
• Word divider
• Word wrapping
• Word joiner (U+2060: ⁠), as well as zero-width no-break space (U+FEFF: )
• Zero-width joiner (U+200D: ‍)
• Zero-width non-joiner (U+200C: ‌)