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{{Short description|Punctuation and accent mark}}
{{About|the punctuation and diacritical mark|the Swedish singer|Tilde (singer)}}
{{Redirect|~|the album|~ (album){{!}}''~'' (album)}}
{{Use dmy dates|date=September 2020}}

{{Infobox symbol
|mark=~{{nbsp}}◌&#x0303;
|name=Tilde (symbol), Combining tilde ([[diacritic]])
|unicode={{unichar|007E|html=}}<br />{{unichar|0303|cwith=◌}} 
|see also=
[[Double tilde (disambiguation) ]]<br />
{{unichar|301C|WAVE DASH|nlink=}}
}}
{{Orthography notation}}

The '''tilde''' ({{IPAc-en|"|t|I|l|d|@}}, also {{IPAc-en|"|t|I|l|d|,_|-|d|i||,_|-|d|eI}})<ref>{{Cite book|title=The Chambers Dictionary|publisher=Chambers|year=2003|isbn=0-550-10105-5|edition=9th|chapter=tilde}}</ref> is a [[grapheme]] {{angbr|'''˜'''}} or {{angbr|'''~'''}} with a number of uses. The name of the character came into [[English language|English]] from [[Spanish language|Spanish]] {{wikt-lang|es|tilde}}, which in turn came from the [[Latin]] {{wikt-lang|la|titulus}}, meaning 'title' or 'superscription'.<ref>{{AHDict|tilde}}</ref> Its primary use is as a [[diacritic]] (accent) in combination with a base letter. Its freestanding form is used in modern texts mainly to indicate [[approximation]].

==History==

===Use by medieval scribes===

The tilde was originally one of a variety of marks written over an omitted letter or several letters as a [[scribal abbreviation]] (a "mark of contraction").<ref>Martin, Charles Trice (1910). The record interpreter : a collection of abbreviations, Latin words and names used in English historical manuscripts and records (2nd ed.). London, preface, p.5 [https://archive.org/details/recordinterprete00martuoft/page/n9/mode/2up]</ref> Thus, the commonly used words ''[[Anno Domini]]'' were frequently abbreviated to ''A<sup>o</sup> Dñi'', with an elevated terminal with a contraction mark placed over the "n". Such a mark could denote the omission of one letter or several letters. This saved on the expense of the scribe's labor and the cost of vellum and ink. Medieval European charters written in Latin are largely made up of such abbreviated words with contraction marks and other abbreviations; only uncommon words were given in full.

The text of the [[Domesday Book]] of 1086, relating for example, to the [[manor of Molland]] in [[Devon]] (see adjacent picture), is highly [[Scribal abbreviation|abbreviated]] as indicated by numerous tildes.

[[File:Text of Exeter Domesday Book of 1086.jpg|center|thumb|upright=1.35|Text of Exeter [[Domesday Book]] of 1086]]

The text with abbreviations expanded is as follows:
{{blockquote|{{lang|la|Mollande tempore regis Eduardi geldabat pro quattuor hidis et uno ferling. Terra est quadraginta carucae. In dominio sunt tres carucae et decem servi et triginta villani et viginti bordarii cum sedecim carucis. Ibi duodecim acrae prati et quindecim acrae silvae. Pastura tres leugae in longitudine et latitudine. Reddit<!-- This is a real Latin word, meaning "it yields"; please do not "correct" it. --> quattuor et viginti libras ad pensam. Huic manerio est adjuncta Blachepole. Elwardus tenebat tempore regis Edwardi pro manerio et geldabat pro dimidia hida. Terra est duae carucae. Ibi sunt quinque villani cum uno servo. Valet viginti solidos ad pensam et arsuram. Eidem manerio est injuste adjuncta Nimete et valet quindecim solidos. Ipsi manerio pertinet tercius denarius de Hundredis Nortmoltone et Badentone et Brantone et tercium animal pasturae morarum.}}}}

===Role of mechanical typewriters===
{{more|Dead key|Diacritic}}
[[File:Olivetti Lettera 32.JPG|thumb|An [[Olivetti Lettera 32]] typewriter (Portuguese Model) with tilde (and circumflex) dead-key beside {{keypress|Ç}} ]]
[[File:Idazmakina.jpg|thumb|Spanish typewriter (QWERTY keyboard) with dead keys for acute, circumflex, diaeresis and grave accents. Ñ/ñ is present as a precomposed character only.]]<!-- Typewriter made in Italy for Spanish market -->

On [[typewriter]]s designed for languages that routinely use [[diacritic]]s (accent marks), there are two possible solutions. Keys can be dedicated to [[precomposed character]]s or alternatively a [[dead key]] mechanism can be provided. With the latter, a mark is made when a dead key is typed, but unlike normal keys, the paper carriage does not move on and thus the next letter to be typed is printed under that accent. Typewriters for [[Spanish (language)|Spanish]] typically have a dedicated key for [[Ñ]]/ñ but, as [[Portuguese (language)|Portuguese]] uses [[Ã]]/ã and [[Õ]]/õ, a single dead-key (rather than take two keys to dedicate) is the most practical solution.

The tilde symbol did not exist independently as a [[movable type]] or [[Hot metal typesetting|hot-lead]] printing character since the [[type case]]s for Spanish or Portuguese would include [[sort (typesetting)|sort]]s for the accented forms.

===The centralized ASCII tilde <span class="anchor" id="ASCII tilde (U+007E)"></span>===
{| align=right cellpadding="2px" border=0 style="margin-left:2em"
 | align=right |Serif:
 | style="font-size:large; font-family:serif" |—~—
 |-
 | align=right |Sans-serif:
 | style="font-size:large; font-family:sans-serif" |—~—
 |-
 | align=right |Monospace:
 | style="font-size:large; font-family:monospace" |—~—
 |-
 | colspan=2 style="font-size:small" |A free-standing tilde between two em dashes<br/>in three font families
 |}
The first [[ASCII]] standard (X3.64-1963) did not have a tilde.<ref name="Mackenzie_1980">{{cite book |url=https://textfiles.meulie.net/bitsaved/Books/Mackenzie_CodedCharSets.pdf |title=Coded Character Sets, History and Development |series=The Systems Programming Series |author-last=Mackenzie |author-first=Charles E. |date=1980 |edition=1 |publisher=[[Addison-Wesley Publishing Company, Inc.]] |isbn=978-0-201-14460-4 |lccn=77-90165  |access-date=2019-08-25 |archive-url=https://web.archive.org/web/20160526172151/https://textfiles.meulie.net/bitsaved/Books/Mackenzie_CodedCharSets.pdf |archive-date=May 26, 2016 |url-status=live |df=mdy-all }}</ref>{{rp|246}} Like Portuguese and Spanish, the French, German and Scandinavian languages also needed symbols in excess of the basic 26 needed for English. The [[American Standards Association|ASA]] worked with and through the [[CCITT]] to internationalize the code-set, to meet the basic needs of at least the Western European languages.

{{blockquote|It appears to have been at their May 13–15, 1963 meeting that the CCITT decided that the proposed ISO 7-bit code standard would be suitable for their needs if a lower case alphabet and five diacritical marks [...] were added to it.<ref>{{cite web |title=Meeting of CCITT Working Party on the New Telegraph Alphabet |url= https://www.cl.cam.ac.uk/~mgk25/ucs/ascii-history/ccit.html |publisher=CCITT |date=May 15, 1963}} See Paragraph 3.</ref> At the October 29–31 meeting, then, the ISO subcommittee altered the ISO draft to meet the CCITT requirements, replacing the up-arrow and left-arrow with diacriticals, adding diacritical meanings to the apostrophe and quotation mark, and making the [[number sign]] a dual{{efn|alternative association for the same [[code point]]}} for the tilde.<ref>{{cite web |title=Memorandum to Members, Alternates, and Consultants of A.S.A. X3.2 and task groups |vauthors=((L. L. Griffin, Chairman, X3.2)) | publisher=US Department of the Navy |url=https://www.cl.cam.ac.uk/~mgk25/ucs/ascii-history/iso.html |page=8 |date=29 November 1963}}</ref>|source=Yucca's free information site (which cites the original sources).<ref>{{cite web|url=https://jkorpela.fi/latin1/ascii-hist.html#60|title=Character histories: notes on some ASCII code positions}}</ref>}}
Thus ISO{{nbsp}}646 was born (and the ASCII standard updated to X3.64-1967), providing the tilde and other symbols as optional characters.<ref name="Mackenzie_1980" />{{rp|247}}{{efn|ISO{{nbsp}}646 (and ASCII, which it includes) is a standard for 7-bit encoding, providing just 96 printable characters (and 32 [[control characters]]). This was insufficient to meet the needs of Western European languages and so the standard specifies certain [[code points]] that are available for national variation. With the arrival of 8-bit "[[extended ASCII]]", this issue was largely mitigated, though not fully resolved until [[Unicode]] was established.}}

ISO{{nbsp}}646 and ASCII incorporated many of the overprinting lower-case diacritics from typewriters, including tilde. Overprinting was intended to work by putting a [[backspace]] code between the codes for letter and diacritic.<ref>{{cite web |title= Second ISO draft proposal {{!}} 6 and 6 bit character codes for information processing interchange |publisher =ISO |date=December 1963 |url=https://www.cl.cam.ac.uk/~mgk25/ucs/ascii-history/draft.html}} See paragraph 2</ref> {{Citation needed span|However even at that time, mechanisms that could do this or any other overprinting were not widely available, did not work for capital letters, and were impossible on video displays, with the result that this concept failed to gain significant acceptance. Consequently, many of these free-standing diacritics (and the [[underscore]]) were quickly reused by software as additional syntax, basically becoming new types of syntactic symbols that a programming language could use. As this usage became predominant, [[type design]] gradually evolved so these diacritic characters became larger and more vertically centered, making them useless as overprinted diacritics but much easier to read as free-standing characters that had come to be used for entirely different and novel purposes. Most modern fonts align the plain ASCII "[[spacing character|spacing]]" (free-standing) tilde at the same level as [[dash]]es, or only slightly higher.|date=October 2024}}

The free-standing tilde is at code 126 in ASCII, where it was inherited into Unicode as U+007E.

A similar shaped mark ({{char|⁓}}) is known in typography and [[lexicography]] as a [[swung dash]]: these are used in dictionaries to indicate the omission of the entry word.<ref>{{Citation | url = http://wordnetweb.princeton.edu/perl/webwn?s=swung+dash&sub=Search+WordNet&o2=&o0=1&o8=1&o1=1&o7=&o5=&o9=&o6=&o3=&o4=&h=000000000000 | title = WordNet | type = search | edition = 3.0 | contribution = Swung dash}}</ref>

===Connection to Spanish===
{{Main|Ñ}}
[[File:Logotipo del Instituto Cervantes.svg|thumbnail|left|Logo of the Instituto Cervantes]]
[[File:Logo de CNN en Español (2010-2015).svg|thumbnail|right|Logo of CNN en Español]]
As indicated by the etymological origin of the word "tilde" in English, this symbol has been closely associated with the [[Spanish language]]. The connection stems from the use of the tilde above the letter {{angbr|n}} to form the (different) letter {{angbr|ñ}} in Spanish, a feature shared by only [[#Palatal n|a few other languages]], most of which are historically connected to Spanish. This peculiarity can help non-native speakers quickly identify a text as being written in Spanish with little chance of error. Particularly during the 1990s, Spanish-speaking intellectuals and news outlets demonstrated support for the language and the culture by defending this letter against [[globalisation]] and [[computer]]isation trends that threatened to remove it from keyboards and other standardised products and codes.<ref>{{cite web|title=26 argumentos para seguir defendiendo la Ñ|url=http://www.larazon.es/historico/651-26-argumentos-para-seguir-defendiendo-la-n-SLLA_RAZON_352314#.Ttt1ZN8CWth9pio|website=La Razón|access-date=31 January 2016|date=11 January 2011}}</ref><ref>{{Cite web |url=http://www.abc.com.py/edicion-impresa/internacionales/batalla-de-la-n-una-aventura-quijotesca-para-defender-el-alma-de-la-lengua-797718.html |title=Batalla de la Ñ: Una aventura quijotesca para defender el alma de la lengua |last=AFP |date=18 November 2004 |website=Periódico ABC Paraguay |access-date=31 January 2016}}</ref> The [[Instituto Cervantes]], founded by [[Spanish government|Spain's government]] to promote the Spanish language internationally, chose as its logo a highly stylised {{char|Ñ}} with a large tilde. The 24-hour news channel [[CNN]] in the US later adopted a similar strategy on its existing logo for the launch of its [[CNN en Español|Spanish-language version]], therefore being written as CN͠N. And similarly to the [[National Basketball Association]] (NBA), the [[Spain men's national basketball team]] is nicknamed "ÑBA".

In Spanish itself the word {{lang|es|tilde}} is used more generally for diacritics, including the stress-marking acute accent.<ref>[http://dle.rae.es/?id=ZkHNOE8 Diccionario de la lengua española], Real Academia Española</ref> The diacritic {{char|~}} is more commonly called {{lang|es|virgulilla}} or {{lang|es|la tilde de la eñe}}, and is not considered an accent mark in Spanish, but rather simply a part of the letter {{char|ñ}} (much like [[tittle|the dot]] over {{char|ı}} makes an {{char|i}} character that is familiar to readers of English).

==Usage==
=== Letters with tilde<span class="anchor" id="Letters with tilde"></span> ===
Unicode encodes a number of cases of "letter with tilde" as [[precomposed character]]s and these are displayed below.  In addition, many more symbols may be composed using the [[combining character]] facility ({{unichar|0303|Combining tilde|cwith=◌|nlink=combining character}}, {{unichar|0330|Combining tilde below|cwith=◌|nlink=combining character}} and others) that may be used with any letter or other diacritic to create a customised symbol but this does not mean that the result has any real-world application and are not shown in the table. <!-- AND PLEASE DO NOT TRY TO ADD THEM -->
{{Letters with diacritic/header}}<!--
-->{{hlist|{{Letters with diacritic/diacritic|format=char|d=tilde}}<!--
-->{{Letters with diacritic/scriptname|1=Latin}}[[Ã|Ã{{NNBSP}}ã]]
| [[Ẵ|Ẵ{{NNBSP}}ẵ]]
| [[Ẫ|Ẫ{{NNBSP}}ẫ]]
| [[ᵬ]]
| [[ᵭ]]
| [[Ẽ|Ẽ{{NNBSP}}ẽ]]
| [[Ễ|Ễ{{NNBSP}}ễ]]
| [[Ḛ|Ḛ{{NNBSP}}ḛ]]
| [[ᵮ]]
| [[Ĩ|Ĩ{{NNBSP}}ĩ]]
| [[Ḭ|Ḭ{{NNBSP}}ḭ]]
| [[ɫ]]
| [[ᵯ]]
| [[Ñ|Ñ{{NNBSP}}ñ]]
| [[ᵰ]]
| [[Õ|Õ{{NNBSP}}õ]]
| [[Ỗ|Ỗ{{NNBSP}}ỗ]]
| [[Ỡ|Ỡ{{NNBSP}}ỡ]]
| [[Ṍ|Ṍ{{NNBSP}}ṍ]]
| [[Ṏ|Ṏ{{NNBSP}}ṏ]]
| [[Ȭ|Ȭ{{NNBSP}}ȭ]]
| [[ᵱ]]
| [[ᵳ]]
| [[ᵲ]]
| [[ꭨ]] <!-- LATIN SMALL LETTER TURNED R WITH MIDDLE TILDE -->
| [[ᵴ]]
| [[ᵵ]]
| [[Ũ|Ũ{{NNBSP}}ũ]]
| [[Ữ|Ữ{{NNBSP}}ữ]]
| [[Ṹ|Ṹ{{NNBSP}}ṹ]]
| [[Ṵ|Ṵ{{NNBSP}}ṵ]]
| [[Ṽ|Ṽ{{NNBSP}}ṽ]]
| [[Ỹ|Ỹ{{NNBSP}}ỹ]]
| [[ᵶ]]
<!-- No precomposed {{Letters with diacritic/scriptname|1=Greek}} -->
<!-- No precomposed {{Letters with diacritic/scriptname|1=Cyrillic}} -->
}}
{{Letters with diacritic/footer}}

A tilde diacritic can be added to almost any character by using a [[combining character|combining]] tilde. Greek  and Cyrillic  letters with tilde ([[Α͂|Α͂{{NNBSP}}ᾶ]], [[Η͂|Η͂{{NNBSP}}ῆ]],  [[Ι͂|Ι͂{{NNBSP}}ῖ]], ῗ, [[Υ͂|Υ͂{{NNBSP}}ῦ]], ῧ and [[А̃|А̃{{NNBSP}}а̃]], [[Ә̃|Ә̃ ә̃]], [[Е̃|Е̃{{NNBSP}}е̃]], [[И̃|И̃{{NNBSP}}и̃]], [[О̃|О̃{{NNBSP}}о̃]], [[У̃|У̃{{NNBSP}}у̃]], [[Ј̃|Ј̃{{NNBSP}}j̃]]) are formed using this method.

===Common use in English<span class="anchor" id="Common use"></span>===
<!-- Advice to editors: this section is about use in English. Uses in other languages (e.g, Japanese) and specialist uses (e.g., Computing, Mathematics) go in those sections, not here. -->
The [[English language]] does not use the tilde as a diacritic, though it is used in some [[loanword]]s. The standalone form of the symbol is used more widely. Informally,<ref name=wolfram_tilde /> it means [[approximation|"approximately"]], "about", or "around", such as "~30 minutes before", meaning "''approximately'' 30 minutes before".<ref name="bymath1"/><ref>{{cite web|url=https://www.microsoft.com/typography/developers/fdsspec/maths.aspx|title=Character design standards – Maths|website=[[Microsoft]]}}</ref> It may also mean "similar to",<ref name="htmlhelp1">{{cite web| first =Liam | last = Quinn |url=http://htmlhelp.com/reference/html40/entities/symbols.html |title=HTML 4.0 Entities for Symbols and Greek Letters |publisher=HTML help |access-date=11 November 2011}}</ref> including "of the same [[order of magnitude]] as",<ref name=wolfram_tilde>{{cite web|url=http://mathworld.wolfram.com/Tilde.html | publisher = Wolfram/MathWorld | title = Tilde |date=3 November 2011 |access-date=11 November 2011}}</ref> such as "{{math |{{mvar |x}} ~ {{mvar|y}}}}" meaning that {{mvar|x}} and {{mvar|y}} are of the same order of magnitude. Another approximation symbol is the [[approximation#Mathematics|double tilde]] {{char|≈}}, meaning "approximately/almost equal to".<ref name="bymath1" /><ref name="htmlhelp1"/><ref>{{cite web |url=http://www.solving-math-problems.com/math-symbols-approximately-equal.html |title=Math Symbols... Those Most Valuable and Important: Approximately Equal Symbol |publisher=Solving Math problems |date=20 September 2010 |access-date=11 November 2011 |archive-date=9 November 2011 |archive-url=https://web.archive.org/web/20111109213922/http://www.solving-math-problems.com/math-symbols-approximately-equal.html |url-status=dead }}</ref> The tilde is also used to indicate [[congruence (geometry)|congruence]] of shapes by placing it over an {{char|1==}} symbol, thus {{char|≅}}.

In more recent digital usage, tildes on either side of a word or phrase have sometimes come to convey a particular tone that "let[s] the enclosed words perform both sincerity and irony", which can pre-emptively defuse a negative reaction.<ref name=Bernstein>{{cite web |last1=Bernstein |first1=Joseph |title=The Hidden Language of The ~Tilde~ |url=https://www.buzzfeednews.com/article/josephbernstein/the-hidden-language-of-the-tilde |website=[[BuzzFeed News]] |date=5 January 2015 |language=en}}</ref> For example, [[BuzzFeed News|BuzzFeed]] journalist Joseph Bernstein interprets the tildes in the following [[Twitter#Tweets|tweet]]:
:"in the ~ spirit of the season ~ will now link to some of the (imho) #Bestof2014 sports reads. if you hate nice things, mute that hashtag."
as a way of making it clear that both the author and reader are aware that the enclosed phrase – "spirit of the season" – "is cliche and we know this quality is beneath our author, and we don't want you to think our author is a cliche person generally".<ref name=Bernstein />{{efn|See also [[Air quotes]].}}

Among other uses, the symbol has been used on [[social media]] to [[Irony punctuation|indicate sarcasm]].<ref>{{cite web |title=The Internet Tilde Perfectly Conveys Something We Don't Have the Words to Explain |author= Jess Kimball Leslie | date=June 5, 2017 |website=The Cut |url=https://www.thecut.com/article/why-the-internet-tilde-is-our-most-perfect-tool-for-snark.html}}</ref> It may also be used online, especially in informal writing such as [[fan fiction|fanfiction]], to convey a cutesy, playful, or flirtatious tone.<ref>{{cite web |title=What Are Tildes ( ~ ) And How Do You Use Them?  | date=April 12, 2022 |website=Thesaurus.com |url=https://www.thesaurus.com/e/grammar/tildes/}}</ref>
<!-- Advice to contributors: please do not add your personal experience of memes and the like, unless you can support it by citing a reliable third party source. See wikipedia policy "Wikipedia:No original research". -->

===Diacritical use===
In some languages, the tilde is a [[diacritic]] mark placed over a [[Letter (alphabet)|letter]] to indicate a change in its pronunciation:

====Pitch====
The tilde was firstly used in the [[Greek diacritics|polytonic orthography]] of [[Ancient Greek]], as a variant of the [[circumflex]], representing a rise in [[pitch accent|pitch]] followed by a return to standard pitch.{{Citation needed|date=October 2024}}

====Abbreviation====
[[File:Hic Fabricatur Naves.jpg|right|thumb|''[[Carta marina]]'' showing Finnish economy, with the captions {{lang|la|Hic fabricantur naves}} and {{lang|la|Hic fabricantur [[Bombard (weapon)|bombarde]]}} abbreviated]]
Later, it was used to make [[scribal abbreviation|abbreviations]] in medieval [[Latin language|Latin]] documents. When an {{angle bracket|n}} or {{angle bracket|m}} followed a vowel, it was often omitted, and a tilde (physically, a small {{angle bracket|N}}) was placed over the preceding vowel to indicate the missing letter; this is the origin of the use of tilde to indicate nasalization (compare [[Umlaut (diacritic)#Umlaut history|the development of the umlaut]] as an abbreviation of {{angle bracket|e}}.) The practice of using the tilde over a vowel to indicate omission of an {{angle bracket|n}} or {{angle bracket|m}} continued in printed books in [[French language|French]] as a means of reducing text length until the 17th century. It was also used in [[Portuguese language|Portuguese]] and [[Spanish language|Spanish]].{{Citation needed|date=October 2024}}

The tilde was also used occasionally to make other abbreviations, such as over the letter {{angle bracket|q}}, making {{char|q̃}}, [[wikt:q̃|to signify the word ''que'']] ("that").{{Citation needed|date=October 2024}}

====Nasalization====
It is also as a small {{angle bracket|n}} that the tilde originated when written above other letters, marking a [[Latin language|Latin]] {{angle bracket|n}} which had been [[elision|elided]] in old Galician-Portuguese. In modern [[Portuguese language|Portuguese]] it indicates [[nasalization]] of the base vowel: {{lang|pt|mão}} "hand", from Lat. ''manu-''; {{lang|pt|razões}} "reasons", from Lat. {{lang|la|rationes}}.{{Citation needed|date=October 2024}} This usage has been adopted in the orthographies of several [[Indigenous languages of the Americas|native languages of South America]], such as [[Guarani language|Guarani]] and [[Nheengatu language|Nheengatu]], as well as in the [[International Phonetic Alphabet]] (IPA) and many other phonetic alphabets. For example, {{IPA|[ljɔ̃]}} is the IPA transcription of the pronunciation of the French place-name ''[[Lyon]]''.

In [[Breton language|Breton]], the symbol {{angle bracket|ñ}} after a vowel means that the letter {{angle bracket|n}} serves only to give the vowel a nasalised pronunciation, without being itself pronounced, as it normally is. For example, {{angle bracket|an}} gives the pronunciation {{IPA|[ãn]}} whereas {{angle bracket|añ}} gives {{IPA|[ã]}}.

In the [[Deutsche Morgenländische Gesellschaft|DMG]] romanization of [[Tunisian Arabic]], the tilde is used for nasal vowels õ and ṏ.

====Palatal n====
{{main|Ñ}}
The tilded {{angle bracket|n}} ({{angle bracket|ñ}}, {{angle bracket|Ñ}}) developed from the digraph {{angle bracket|nn}} in Spanish. In this language, {{angle bracket|ñ}} is considered a separate letter called ''[[Ñ|eñe]]'' ({{IPA|es|ˈeɲe|IPA}}), rather than a letter-diacritic combination; it is placed in Spanish dictionaries between the letters {{angle bracket|n}} and {{angle bracket|o}}. In Spanish, the word ''tilde'' actually refers to diacritics in general, e.g. the acute accent in ''José'',<ref>{{cite book |title=Ortografía de la lengua española |year=2010 |publisher=Real Academia Española |location=Madrid |isbn=978-84-670-3426-4 |page=279 }}</ref> while the diacritic in {{angle bracket|ñ}} is called "virgulilla" ({{IPA|es|birɣuˈliʝa|IPA}}) ([[yeísta]]) or  ({{IPA|es|birɣuˈliʎa|IPA}}) (non-yeísta).  <ref>{{Cite web |url=http://lema.rae.es/drae/?val=virgulilla |title=Lema en la RAE |publisher=[[Real Academia Española]] |access-date=10 October 2015}}</ref> Current languages in which the tilded {{angle bracket|n}} ({{angle bracket|ñ}}) is used for the [[palatal nasal]] consonant {{IPA|/ɲ/}} include
{{div col|colwidth=8em}}
* [[Asturian language|Asturian]]
* [[Aymara language|Aymara]]
* [[Basque language|Basque]]
* [[Chamorro language|Chamorro]]
* [[Filipino language|Filipino]]
* [[Galician language|Galician]]
* [[Guaraní language|Guaraní]]
* [[Iñupiaq language|Iñupiaq]]
* [[Mapudungun]]
* [[Papiamento]]
* [[Quechua languages|Quechua]]
* [[Spanish language|Spanish]]
* [[Tetum language|Tetum]]
* [[Wolof language|Wolof]]
{{div col end}}

====Tone====
In [[Vietnamese language|Vietnamese]], a tilde over a vowel represents a creaky rising [[tone (linguistics)|tone]] (''ngã''). Letters with the tilde are not considered separate letters of the [[Vietnamese alphabet]].

====International Phonetic Alphabet====
{{uncited section|date=June 2024}}
In [[phonetics]], a tilde is used as a [[IPA diacritics|diacritic that is placed]] above a letter, below it or [[superimpose]]d onto the middle of it:

* A tilde above a letter indicates [[nasalization]], e.g. {{IPA|[ã], [ṽ]}}.
* A tilde superimposed onto the middle of a letter indicates [[velarization]] or [[pharyngealization]], e.g. {{IPA|[ɫ], [z̴]}}. If no precomposed [[Unicode]] character exists, the Unicode character {{unichar|0334| COMBINING TILDE OVERLAY|cwith=◌}} can be used to generate one.
* A tilde below a letter indicates [[Creaky voice|laryngealisation]], e.g. {{IPA|[d̰]}}. If no precomposed Unicode character exists, the Unicode character {{unichar|0330| COMBINING TILDE BELOW|cwith=◌}} can be used to generate one.

A tilde between two [[phoneme]]s indicates optionality, or "alternates with". E.g. {{angbr IPA|ɕ ~ ʃ}} could indicate that the sounds may alternate depending on context ([[free variation]]), or that they vary based on region or speaker, or some other variation.

====Letter extension====
In [[Estonian language|Estonian]], the symbol {{angle bracket|õ}} stands for the [[close-mid back unrounded vowel]], and it is considered an independent letter.

==== Modern Usage ====
In modern [[internet slang]], the tilde can be used to signify endearment or love, i.e. "Hello master~". It is commonly used in the [[Furry fandom|furry]] and [[femboy]] communities and can also be used as a diminutive, akin to adding the "ee" sound to the end of a word.{{citation needed|date=October 2024}}

====Other uses====
Some languages and alphabets use the tilde for other purposes, such as:
* [[Arabic script]]: A symbol resembling the tilde ({{unichar|0653|ARABIC MADDAH ABOVE|cwith=ـ|nlink=Arabic diacritics#Maddah}}) is used over the letter {{angle bracket|ا}} ({{IPA|/a/}}) to become <big>{{angle bracket|[[آ]]}}</big>, denoting a long {{IPA|/ʔaː/}} sound.
* [[Guaraní language|Guaraní]]: The tilded {{angle bracket|[[G̃]]}} (note that {{angle bracket|G/g}} with tilde is not available as a precomposed glyph in [[Unicode]]) stands for the [[velar nasal]] consonant. Also, the tilded {{angle bracket|y}} ({{angle bracket|Ỹ}}) stands for the nasalized upper central rounded vowel {{IPA|[ɨ̃]}}. [[Munduruku language|Munduruku]], Parintintín, and two older spellings of Filipino words also use {{angle bracket|g̃}}. 
* [[Syriac script]]: A tilde (~) under the letter ''[[Kaph]]'' represents a {{IPA|[t͡ʃ]}} sound, transliterated as ''ch'' or ''č''.<ref>[[Eberhard Nestle|Nestle, Eberhard]] (1888). ''Syrische Grammatik mit Litteratur, Chrestomathie und Glossar''. Berlin: H. Reuther's Verlagsbuchhandlung. [translated to English as ''Syriac grammar with bibliography, chrestomathy and glossary'', by R. S. Kennedy. London: Williams & Norgate 1889. p. 5].</ref>
* [[Estonian phonology|Estonian]] and [[Võro language|Võro]] use the tilde above the letter o ('''õ''') to indicate the vowel {{IPA|[ɤ]}}, a rare sound among languages.
* [[Unicode]] has a [[combining character|combining]] vertical tilde character: {{unichar|033E|COMBINING VERTICAL TILDE|cwith=◌}}. It is used to indicate [[tone accent|middle tone]] in linguistic transcription of certain dialects of the [[Lithuanian language]],<ref>Lithuanian Standards Board (LST), [http://std.dkuug.dk/jtc1/sc2/wg2/docs/n2597.pdf proposal for a zigzag diacritic]</ref> and was also used historically in the letter [[х̾]], which was part of the [[Cyrillization of Polish|Polish Cyrillic alphabet]] of the late 19th century.
* [[Resurrección María de Azkue]]'s 1906 Basque dictionary used an idiosyncratic spelling including {{anglebracket|[[ã]] [[d̃]] [[ẽ]] [[ĩ]] [[l̃]] [[ñ]] [[õ]] [[s̃]] [[t̃]] [[ũ]] [[x̃]]}}.<ref name="Azkue">{{cite web |title=R. M. de Azkue: "Euskara-Gaztelania-Frantsesa Hiztegia" / "Diccionario Vasco-Español-Francés" online -Tutorial de uso |url=https://www.aurtenbai.eus/dok/Azkue-tutoriala_ES.pdf |publisher=Aurten Bai Fundazioa |access-date=12 February 2024 |page=6 |language=es |quote=El autor usaba fuentes propias para representar fenómenos propios de algunos de los dialectos del euskera. Estos son los caracteres especiales utilizados en el diccionario: ã d̃ ẽ ĩ l̃ ñ õ s̃ t̃ ũ x̃.}}</ref>

===Punctuation===
The tilde is used in various ways in punctuation, including:

====Range====
In some languages (such as in French),{{cn|date=July 2024}} a tilde or a tilde-like [[wave dash]] (Unicode: {{unichar|301C|wave dash}}) may be used as a [[punctuation]] mark (instead of an unspaced [[hyphen]], [[en dash]] or [[em dash]]) between two [[number]]s, to indicate a [[Interval (mathematics)|range]]. Doing so avoids the risk of confusion with [[subtraction]] or a hyphenated number (such as a part number or model number). For example, "12~15" means "12 to 15", "~3" means "up to three", and "100~" means "100 and greater".{{cn|date=December 2023}} [[Languages of East Asia|East Asian languages]] almost always use this convention, but it is sometimes done for clarity in some other languages as well. [[Chinese language|Chinese]] uses the wave dash and [[Halfwidth and fullwidth forms|full-width]] em dash interchangeably for this purpose. In English, the tilde is often used to express ranges and model numbers in [[electronics]], but rarely in formal grammar or in type-set documents, as a wavy dash preceding a number sometimes represents an approximation (see below).

The '''range tilde''' is used for various purposes in [[French language|French]], but only to denote ranges of numbers (e.g., {{lang|fr|«&nbsp;21~32 degrés Celsius&nbsp;»}}" means "21 to 32 degrees Celsius"){{cn|date=May 2024}}

(The symbol {{unichar|2248}} (a [[double tilde (disambiguation)|double tilde]])  is also used in French, for example, {{lang|fr|«&nbsp;≈400 mètres&nbsp;»}} means "approximately 400 meters"{{cn|date=May 2024}}.)

==== Approximation ====
{{see also|Approximation}}
Before a number the tilde can mean 'approximately'; '~42' means 'approximately 42'.<ref>
{{Cite web  | url = http://www.linfo.org/tilde.html | title = Tilde Definition | website=linfo.org | publisher = The Linux Information Project  | date = 24 June 2005 | access-date= 27 January 2020}}</ref> When used with [[currency symbol]]s that precede the number (national conventions differ), the tilde precedes the symbol, thus for example '~$10' means 'about ten dollars'.<ref>{{Cite web
|url=https://english.stackexchange.com/questions/116048/using-a-tilde-with-currency |title=Using a tilde with currency|website=[[Stackexchange]]}}</ref>{{better source|reason=Not a reliable source|date=February 2024}}

The symbols <big>≈</big> (almost equal to) and <big>≅</big> (approximately equal to) are among the other [[approximation#Unicode|symbols used to express approximation]].

====Japanese====
{{further|Japanese punctuation#Wave dash}}

The {{Nihongo|'''wave dash'''|波ダッシュ|nami dasshu}} is used for various purposes in Japanese, including to denote ranges of numbers (e.g., ''5〜10'' means between 5 and 10) in place of dashes or brackets, and to indicate origin. The wave dash is also used to separate a title and a subtitle in the same line, as a [[Colon (punctuation)|colon]] is used in English.

When used in conversations via email or instant messenger it may be used as a [[sarcasm mark]] {{citation needed|date=January 2024}}. 

The sign is used as a replacement for the {{transliteration|ja|[[Chōonpu|chōon]]}}, katakana character, in Japanese, extending the final syllable.

=====Unicode and Shift JIS encoding of wave dash=====
{{multiple image
| align = right
| image1 = Wave Dash.svg
| width1 = 100
| alt1 = Correct JIS wave dash
| caption1 = Correct JIS wave dash, current in Unicode
| image2 = Wave Dash2.svg
| width2 = 100
| alt2 = Previous Unicode wave dash (incorrect)
| caption2 = Previous Unicode wave dash (incorrect)
| footer = 
}} 
In practice the {{Nihongo|full-width tilde|全角チルダ|zenkaku chiruda}} (Unicode {{unichar|FF5E|fullwidth tilde}}), is often used instead of the {{Nihongo|wave dash|波ダッシュ|nami dasshu}} (Unicode {{unichar|301C|wave dash}}), because the [[Shift JIS]] code for the wave dash, 0x8160, which should be mapped to U+301C,<ref>{{Citation | chapter-url = http://x0213.org/codetable/sjis-0213-2004-std.txt | title = JIS X 0213:2004 | chapter = Appendix 1: Shift_JIS-2004 vs Unicode mapping table | publisher = X 0213}}.</ref><ref>{{Citation | url = https://www.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/JIS/SHIFTJIS.TXT | title = Shift-JIS to Unicode | publisher = Unicode}}.</ref> is instead mapped to U+FF5E<ref>{{cite web|url=http://www.microsoft.com/globaldev/reference/dbcs/932/932_81.htm |title=Windows 932_81 |publisher=Microsoft | access-date=2010-07-30}}</ref> in [[code page 932 (Microsoft Windows)|Windows code page 932]] ([[Microsoft]]'s [[code page]] for Japanese), a widely used extension of Shift JIS.

This decision avoided a shape definition error in the original (6.2) Unicode code charts:<ref name="U6.2">{{Citation |url=http://www.unicode.org/charts/PDF/U3000.pdf |archive-url=https://web.archive.org/web/20130827100409if_/http://www.unicode.org/charts/PDF/U3000.pdf |archive-date=2013-08-27  | title = CJK Symbols and Punctuation (Unicode 6.2) | type = chart | publisher = Unicode}}.</ref> the wave dash reference glyph in JIS / Shift JIS<ref>{{cite iso-ir |number=87 |title=Japanese Graphic Character Set for Information Interchange |id-in-title=yes |sponsor=Japanese National Committee on ISO/TC97/SC2}}</ref><ref name="jisplane1">{{cite iso-ir | number = 233 | title = Japanese Graphic Character Set for Information Interchange, Plane 1 (Update of ISO-IR 228)| id-in-title = yes | sponsor = Japanese Industrial Standards Committee | sponsor-link = Japanese Industrial Standards Committee}}</ref> matches the Unicode reference glyph for U+FF5E {{resize|FULLWIDTH TILDE}},<ref>{{Citation | url = https://www.unicode.org/charts/PDF/UFF00.pdf | title = Halfwidth and Fullwidth Forms | type = chart | publisher = Unicode}}.</ref> while the original reference glyph for U+301C<ref name="U6.2" /> was reflected, incorrectly,<ref name="errata8">{{citation|url=https://www.unicode.org/versions/Unicode8.0.0/erratafixed.html|title=Errata Fixed in Unicode 8.0.0|publisher=Unicode}}</ref> when Unicode imported the JIS wave dash. In other platforms such as the [[classic Mac OS]] and [[macOS]], 0x8160 is correctly mapped to U+301C. It is generally difficult, if not impossible, for users of Japanese Windows to type U+301C, especially in legacy, non-Unicode applications.

A similar situation exists regarding the Korean [[KS X 1001]] character set, in which Microsoft maps the [[EUC-KR]] or [[Unified Hangul Code|UHC]] code for the wave dash (0xA1AD) to {{unichar|223C|Tilde Operator}},<ref>{{cite web|url=https://icu4c-demos.unicode.org/icu-bin/convexp?conv=windows-949-2000&b=A1&s=ALL#layout|title=windows-949-2000 (lead byte A1)|work=ICU Demonstration – Converter Explorer|publisher=International Components for Unicode}}</ref><ref name="mskrtilde">{{cite web|url=https://msdn.microsoft.com/en-us/library/cc194958.aspx|title=Lead Byte A1-A2 (Code page 949)|work=MSDN|date=6 February 2008 |publisher=Microsoft}}</ref> while [[IBM]] and [[Apple, Inc|Apple]] map it to U+301C.<ref>{{cite web|url=https://icu4c-demos.unicode.org/icu-bin/convexp?conv=ibm-1363_P110-1997&b=A1&s=ALL#layout|title=ibm-1363_P110-1997 (lead byte A1)|work=ICU Demonstration – Converter Explorer|publisher=International Components for Unicode}}</ref><ref>{{cite web|url=https://icu4c-demos.unicode.org/icu-bin/convexp?conv=euc-kr&b=A1&s=ALL#layout|title=euc-kr (lead byte A1)|work=ICU Demonstration – Converter Explorer|publisher=International Components for Unicode}}</ref><ref name="applekrtilde">{{cite web|url=https://unicode.org/Public/MAPPINGS/VENDORS/APPLE/KOREAN.TXT|title=Map (external version) from Mac OS Korean encoding to Unicode 3.2 and later.|publisher=Apple}}</ref> Microsoft also uses U+FF5E to map the KS X 1001 raised tilde (0xA2A6),<ref name="mskrtilde" /> while Apple uses {{unichar|02DC|small tilde}}.<ref name="applekrtilde" />

The current Unicode reference glyph for U+301C has been corrected<ref name="errata8"/> to match the JIS standard<ref>{{Citation | url = https://www.unicode.org/charts/PDF/U3000.pdf | title = CJK Symbols and Punctuation | type = chart | publisher = Unicode}}</ref> in response to a 2014 proposal, which noted that while the existing Unicode reference glyph had been matched by fonts from the discontinued [[Windows XP]], all other major platforms including later versions of Microsoft Windows shipped with fonts matching the JIS reference glyph for U+301C.<ref>{{Citation | url=https://www.unicode.org/L2/L2014/14198-wave-dash.pdf | title=L2/14-198: Proposal for the modification of the sample character layout of WAVE_DASH (U+301C) | last=Komatsu | first=Hiroyuki}}</ref>

The JIS / Shift JIS wave dash is still formally mapped to U+301C as of [[JIS X 0213]],<ref>{{Citation | url=http://x0213.org/codetable/sjis-0213-2004-std.txt | title=Shift_JIS-2004 (JIS X 0213:2004 Appendix 1) vs Unicode mapping table | publisher=x0213.org}}</ref> whereas the [[WHATWG]] Encoding Standard used by [[HTML5]] follows Microsoft in mapping 0x8160 to U+FF5E.<ref>{{citation | url=https://encoding.spec.whatwg.org/shift_jis.html | title=Shift_JIS visualization | work=Encoding Standard | publisher=WHATWG}}</ref> These two code points have a similar or identical glyph in several fonts, reducing the confusion and incompatibility.

===Mathematics===

====As a unary operator====
A tilde in front of a single quantity can mean "approximately", "about"<ref name="bymath1">{{Cite web |title=All Elementary Mathematics – Mathematical symbols dictionary |url=http://www.bymath.com/symbols/symbols.html |publisher=Bymath |accessdate=2014-09-25 |archive-date=2 May 2015 |archive-url=https://web.archive.org/web/20150502113549/http://www.bymath.com/symbols/symbols.html |url-status=dead }}</ref> or "of the same [[order of magnitude]] as."

In written [[mathematical logic]], the tilde represents [[negation]]: "~''p''" means "not ''p''", where "''p''" is a [[proposition]]. Modern use often replaces the tilde with the negation symbol (¬) for this purpose, to avoid confusion with [[equivalence relation]]s.

====As a relational operator====

In [[mathematics]], the tilde operator (which can be represented by a tilde or the dedicated character {{unichar|223C|TILDE OPERATOR}}), sometimes called "twiddle", is often used to denote an [[equivalence relation]] between two objects. Thus "{{math|{{mvar|x}} ~ {{mvar|y}}}}" means "{{mvar|x}} is [[equivalence relation|equivalent]] to {{mvar|y}}". It is a weaker statement than stating that {{mvar|x}} [[equality (mathematics)|equals]] {{mvar|y}}. The expression "{{math|{{mvar|x}} ~ {{mvar |y}}}}" is sometimes read aloud as "{{mvar|x}} twiddles {{mvar|y}}", perhaps as an analogue to the verbal expression of "{{math |1={{mvar |x}} = {{mvar|y}}}}".<ref>{{Citation | last = Derbyshire | first = J | title = Prime Obsession: Bernhard Riemann and the Greatest Unsolved Problem in Mathematics | place = New York | publisher = Penguin | year = 2004 | url = http://mathworld.wolfram.com/Tilde.html}}.</ref>

The tilde can indicate approximate equality in a variety of ways. It can be used to denote the [[asymptotic analysis|asymptotic equality]] of two functions. For example, {{math|{{mvar|f}} ({{mvar|x}}) ~ {{mvar |g}}({{mvar |x}})}} means that <math>\lim_{x \to \infty} \frac{f(x)}{g(x)} = 1</math>.<ref name=wolfram_tilde />

A tilde is also used to indicate "[[Approximation|approximately]] equal to" (e.g. 1.902 ~= 2). This usage probably developed as a typed alternative to the [[:Image:Libra.svg|libra symbol]] used for the same purpose in written mathematics, which is an equal sign with the upper bar replaced by a bar with an upward hump, bump, or loop in the middle (︍︍♎&#xFE0E;) or, sometimes, a tilde (≃).{{Citation needed|date=October 2024}} The symbol "≈" is also used for this purpose.

In [[physics]] and [[astronomy]], a tilde can be used between two expressions (e.g. {{math|{{mvar|h}} ~ 10<sup>−34</sup> J s}}) to state that the two are of the same [[order of magnitude]].<ref name=wolfram_tilde />

In [[statistics]] and [[probability theory]], the tilde means "is distributed as";<ref name = wolfram_tilde /> see [[random variable]](e.g. X ~ B(n,p) for a binomial distribution).

A tilde can also be used to represent geometric [[Similarity (geometry)|similarity]] (e.g. {{math |∆{{mvar |ABC}} ~ ∆{{mvar|DEF}}}}, meaning [[triangle]] {{mvar|ABC}} is similar to {{mvar|DEF}}). A triple tilde ('''≋''') is often used to show [[congruence (geometry)|congruence]], an equivalence relation in geometry.{{Citation needed|date=October 2024}}

In [[graph theory]], the tilde can be used to represent adjacency between vertices. The edge <math>(x,y)</math> connects vertices <math>x</math> and <math>y</math> which can be said to be adjacent, and this adjacency can be denoted <math>x \sim y</math>.

====As a diacritic====

The symbol "<math>\tilde{f}</math>" is pronounced as "eff tilde" or, informally, as "eff twiddle".<ref>{{cite web |url=http://mathworld.wolfram.com/Tilde.html |title = Tilde |publisher = Wolfram Research |access-date = 4 June 2018}}</ref><ref>{{cite book |url=https://books.google.com/books?id=SY5fZIK63NMC&q=schlange+twiddle&pg=PA53 |title=Proceedings of the Analysis Conference, Singapore 1986 |publisher=Elsevier | year = 1988 | first1 =Stephen TL | last1 = Choy | first2 =Judith Packer | last2 = Jesudason | first3 = Peng Yee | last3 = Lee|isbn=9780080872612 }}</ref> This can be used to denote the [[Fourier transform]] of ''f'', or a [[lift (mathematics)|lift]] of ''f'', and can have a variety of other meanings depending on the context.

A tilde placed below a letter in mathematics can represent a [[Euclidean vector|vector]] quantity (e.g. <math>(x_1, x_2, x_3, \ldots, x_n) = \underset{^\sim}{\mathbf x}</math>).

In [[statistics]] and [[probability theory]], a tilde placed on top of a variable is sometimes used to represent the [[median]] of that variable; thus <math>\tilde{\mathbf y}</math> would indicate the median of the variable <math>\mathbf y</math>. A tilde over the letter n (<math>\tilde{n}</math>) is sometimes used to indicate the [[harmonic mean]].

In machine learning, a tilde may represent a candidate value for a cell state in [[Gated recurrent unit|GRUs]] or [[LSTM]] units. (e.g. c̃)

===Physics===
Often in [[physics]], one can consider an [[equilibrium solution]] to an equation, and then a perturbation to that equilibrium. For the variables in the original equation (for instance <math>X</math>) a substitution <math>X\to x+\tilde{x}</math> can be made, where <math>x</math> is the equilibrium part and <math>\tilde{x}</math> is the perturbed part.

A tilde is also used in [[particle physics]] to denote the hypothetical [[supersymmetric]] partner. For example, an [[electron]] is referred to by the letter ''e'', and its [[superpartner]] the [[selectron (particle)|selectron]] is written ''ẽ''.

In multibody mechanics, the tilde operator maps three-dimensional vectors <math>\boldsymbol{\omega}\in\mathbb{R}^3</math> to skew-symmetrical matrices <math>\tilde{\boldsymbol{\omega}}=\begin{bmatrix}0&-\omega_3& \omega_2\\ \omega_3& 0& -\omega_1\\ -\omega_2&\omega_1&0\end{bmatrix}</math> (see <ref>{{cite journal |last1=Wallrapp |title=Standardization of flexible body modeling in multibody system codes, Part I: Definition of Standard Input Data |date=1994 |volume=22 |issue=3 |pages=283–304 |doi=10.1080/08905459408905214 |journal=Mechanics of Structures and Machines}}</ref> or <ref>{{cite journal |last1=Valembois |first1=R. E. |last2=Fisette |first2=P. |last3=Samin |first3=J. C. |title=Comparison of Various Techniques for Modelling Flexible Beams in Multibody Dynamics |journal=Nonlinear Dynamics |date=1997 |volume=12 |issue=4 |pages=367–397 |doi=10.1023/A:1008204330035|s2cid=122487067 }}</ref>).

===Economics===
For relations involving preference, [[economist]]s sometimes use the tilde to represent [[Preference (economics)#Notation|indifference]] between two or more bundles of goods. For example, to say that a consumer is indifferent between bundles ''x'' and ''y'', an economist would write ''x'' ~ ''y''.

===Electronics===
It can approximate the sine wave symbol (∿, [[Unicode|U+]]223F), which is used in [[electronics]] to indicate [[alternating current]], in place of +, −, or ⎓ for [[direct current]].

===Linguistics===
The tilde may indicate alternating [[allomorph]]s or [[Morphophonology|morphological alternation]], as in {{IPA|//ˈniː~ɛl+t//}} for ''kneel~knelt'' (the [[plus sign#Other uses|plus sign]] '+' indicates a morpheme boundary).<ref>Collinge (2002) ''An Encyclopedia of Language'', §4.2.</ref><ref>{{Cite book | last=Hayes | first=Bruce | author-link=Bruce Hayes (linguist) | title=Introductory Phonology | publisher=John Wiley & Sons | date=2011 | isbn=9781444360134 | pages=87–88 }}</ref>

The tilde may represent some sort of phonetic or phonemic variation between two sounds, which might be [[allophone]]s or in [[free variation]]. For example, {{IPA|[χ ~ x]}} can represent "either {{IPA|[χ]}} or {{IPA|[x]}}".

In [[formal semantics (linguistics)|formal semantics]], it is also used as a notation for the ''[[squiggle operator]]'' which plays a key role in many theories of [[focus (linguistics)|focus]].<ref>{{cite book |last=Buring |first=Daniel |date=2016 |title=Intonation and Meaning |doi=10.1093/acprof:oso/9780199226269.003.0003 |publisher=Oxford University Press |pages=36–41 |isbn=978-0-19-922627-6}}</ref>

===Computing===

[[Computer programmers]] use the tilde in various ways and sometimes call the symbol (as opposed to the diacritic) a '''squiggle''', '''squiggly''', '''swiggle''', or '''twiddle'''. According to the [[Jargon File]], other synonyms sometimes used in programming include '''not''', '''approx''', '''wiggle''', '''enyay''' (after ''[[ñ|eñe]]'') and (humorously) '''sqiggle''' {{IPAc-en|ˈ|s|k|ɪ|ɡ|əl}}.<ref name=":0">{{Cite web |date=2012-01-05 |title=Jargon File 5.0.1 |url=http://cosman246.com/jargon.html |archive-url=https://web.archive.org/web/20130827121341/http://cosman246.com/jargon.html |archive-date=2013-08-27}}</ref>

==== Directories and URLs ====
On [[Unix]]-like [[operating system]]s (including [[AIX]], [[BSD]], [[Linux]] and [[macOS]]), tilde normally indicates the current user's [[home directory]]. For example, if the current user's home directory is {{mono|/home/user}}, then the command {{mono|cd ~}} is equivalent to {{mono|cd /home/user}}, {{mono|cd $HOME}}, or {{mono|cd}}.<ref name=":0" /> This convention derives from the [[Lear-Siegler]] [[ADM-3A]] terminal in common use during the 1970s, which happened to have the tilde symbol and the word "Home" (for moving the cursor to the upper left) on the same key.{{Citation needed|date=November 2008}}<!-- may be true, but we need a source for "derives" --> When prepended to a particular username, the tilde indicates that user's home directory (e.g., {{mono|~janedoe}} for the home directory of user {{mono|janedoe}}, such as {{mono|/home/janedoe}}).<ref>{{Citation | contribution = Tilde expansion | publisher = The GNU project | title = C Library Manual | access-date = 4 July 2010 | url = https://www.gnu.org/s/libc/manual/html_node/Tilde-Expansion.html}}.</ref>

Used in [[Uniform Resource Locator|URLs]] on the [[World Wide Web]], it often denotes a personal website on a [[Unix]]-based server. For example, {{mono|<nowiki>http://www.example.com/~johndoe/</nowiki>}} might be the personal website of John Doe. This mimics the Unix shell usage of the tilde. However, when accessed from the web, file access is usually directed to a [[subdirectory]] in the user's home directory, such as {{mono|/home/''username''/public_html}} or {{mono|/home/''username''/www}}.<ref>{{Citation | contribution = Module mod_userdir | publisher = The Apache foundation | title = HTTP Server Documentation | edition = version 2.0 | access-date = 4 July 2010 | url = http://httpd.apache.org/docs/2.0/mod/mod_userdir.html}}.</ref>

In URLs, the characters {{mono|%7E}} (or {{mono|%7e}}) may substitute for a tilde if an input device lacks a tilde key.{{Ref RFC|3986|p=12}} Thus, {{mono|<nowiki>http://www.example.com/~johndoe/</nowiki>}} and {{mono|<nowiki>http://www.example.com/%7Ejohndoe/</nowiki>}} will behave in the same manner.

==== Computer languages ====
{{More citations needed|section|date=October 2024}}

=====Regex=====
The tilde is used in the [[AWK]] [[programming language]] as part of the pattern match operators for [[regular expression]]s:
*<code>''variable'' ~ /''regex''/</code> returns true if the variable is matched.
*<code>''variable'' !~ /''regex''/</code> returns false if the variable is matched.

A variant of this, with the plain tilde replaced with <code>=~</code>, was adopted in [[Perl]], and this semi-standardization has led to the use of these operators in other programming languages, such as [[Ruby programming language|Ruby]] or the [[SQL]] variant of the database [[PostgreSQL]].

In [[APL (programming language)|APL]] and [[MATLAB]], tilde represents the monadic logical function NOT, and in APL it additionally represents the dyadic [[multiset]] function ''without'' ([[Complement (set theory)#Relative complement|set difference]]).

In [[C (programming language)|C]] the tilde character is used as [[bitwise NOT]] unary [[Operators in C and C++|operator]], following the notation in logic (an <code>!</code> causes a logical NOT, instead). This is also used by most languages based on or influenced by C, such as [[C++]], [[D programming language|D]], [[C Sharp (programming language)|C#]] and [[Julia (programming language)|Julia]]. The [[MySQL|MySQL database]] also use tilde as bitwise invert<ref>{{Cite web|url=https://dev.mysql.com/doc/refman/8.0/en/bit-functions.html#operator_bitwise-invert|title=MySQL :: Reference Manual :: Bit Functions and Operators|website=dev.mysql.com|access-date=2019-12-20}}</ref> as does Microsoft's SQL Server [[Transact-SQL|Transact-SQL (T-SQL)]] language. {{anchor|~~ cast}} [[JavaScript]] also uses tilde as bitwise NOT, and because JavaScript internally uses floats and the bitwise complement only works on integers, numbers are stripped of their decimal part before applying the operation. This has also given rise to using two tildes <code>~~x</code> as a short syntax for a cast to integer (numbers are stripped of their decimal part and changed into their complement, and then back).

In C++ and C#, the tilde is also used as the first character in a [[Class (computer science)|class]]'s [[method (computer science)|method]] name (where the rest of the name must be the same name as the class) to indicate a [[destructor (computer science)|destructor]] – a special method which is called at the end of the [[Object lifetime|object's life]].

In ASP.NET application tilde ('~') is used as a shortcut to the root of the application's virtual directory.

In the [[Cascading Style Sheets|CSS]] stylesheet language, the tilde is used for the indirect adjacent combinator as part of a selector.

In the [[D programming language]], the tilde is used as an [[Array data structure|array]] [[concatenation]] operator, as well as to indicate an object destructor and bitwise not operator. Tilde operator can be overloaded for user types, and binary tilde operator is mostly used to merging two objects, or adding some objects to set of objects. It was introduced because plus operator can have different meaning in many situations. For example, what to do with "120" + "14" ? Is this a string "134" (addition of two numbers), or "12014" (concatenation of strings) or something else? D disallows + operator for arrays (and strings), and provides separate operator for concatenation (similarly [[PHP]] programming language solved this problem by using dot operator for concatenation, and + for number addition, which will also work on strings containing numbers).

In [[Eiffel (programming language)|Eiffel]], the tilde is used for object comparison. If ''a'' and ''b'' denote objects, the Boolean expression ''a'' ~ ''b'' has value true if and only if these objects are equal, as defined by the applicable version of the library routine ''is_equal'', which by default denotes field-by-field object equality but can be redefined in any class to support a specific notion of equality. If ''a'' and ''b'' are references, the object equality expression ''a'' ~ ''b'' is to be contrasted with ''a'' = ''b'' which denotes reference equality. Unlike the call ''a''.''is_equal'' (''b''), the expression ''a'' ~ ''b'' is [[type safety|type-safe]] even in the presence of [[Covariance and contravariance (computer science)|covariance]].

In the [[Groovy (programming language)|Apache Groovy programming language]] the tilde character is used as an operator mapped to the bitwiseNegate() method.<ref>{{cite web|url=http://groovy.codehaus.org/Operator%20Overloading|title=The Groovy programming language – Operators}}{{Dead link|date=September 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Given a String the method will produce a java.util.regex.Pattern. Given an integer it will negate the integer bitwise like in C. <code>=~</code> and <code>==~</code> can in Groovy be used to match a regular expression.<ref>{{Citation | url = http://groovy.codehaus.org/Regular+Expressions | title = Groovy Regular Expression User Guide | publisher = Code haus | access-date = 11 November 2010 | archive-date = 26 July 2010 | archive-url = https://web.archive.org/web/20100726062443/http://groovy.codehaus.org/Regular+Expressions | url-status = dead }}.</ref><ref>{{Citation | url = http://groovy.codehaus.org/FAQ+-+RegExp | title = Groovy RegExp FAQ | publisher = Code haus | access-date = 11 November 2010 | archive-date = 11 July 2010 | archive-url = https://web.archive.org/web/20100711164313/http://groovy.codehaus.org/FAQ+-+RegExp | url-status = dead }}.</ref>

In [[Haskell (programming language)|Haskell]], the tilde is used in type constraints to indicate type equality.<ref>{{Citation | url = http://www.haskell.org/haskellwiki/GHC/Type_families#Equality_constraints | title = Haskell Wiki | contribution = Type Families}}.</ref> Also, in pattern-matching, the tilde is used to indicate a lazy pattern match.<ref>{{cite web|url=http://www.haskell.org/haskellwiki/Lazy_pattern_match|title=Lazy pattern match – HaskellWiki}}</ref>

In the [[Inform]] programming language, the tilde is used to indicate a quotation mark inside a quoted string. <!-- but what does it use to indicate a ~ inside a quoted string? -->

In "text mode" of the [[LaTeX]] typesetting language a tilde diacritic can be obtained using, e.g., <code>\~{n}</code>, yielding "ñ". A stand-alone tilde can be obtained by using <code>\textasciitilde</code> or <code>\string~</code>.
In "math mode" a tilde diacritic can be written as, e.g., <code>\tilde{x}</code>. For a wider tilde <code>\widetilde</code> can be used. The <code>\sim</code> command produce a tilde-like binary relation symbol that is often used in mathematical expressions, and the double-tilde [[≈]] is obtained with <code>\approx</code>. The <code>url</code> package also supports entering tildes directly, e.g., <code><nowiki>\url{http://server/~name}</nowiki></code>.
In both text and math mode, a tilde on its own (<code>~</code>) renders a white space with no line breaking.

In [[MediaWiki]] [[Syntax (programming languages)|syntax]], four tildes are used as a shortcut for a user's signature.

In [[Common Lisp]], the tilde is used as the prefix for format specifiers in format strings.<ref>{{cite web|url=http://www.lispworks.com/documentation/HyperSpec/Body/22_c.htm |title=CLHS: Section 22.3 |publisher=Lispworks.com |date=2005-04-11 |access-date=2010-07-30}}</ref>

In [[Max/MSP]], a tilde is used to denote objects that process at the computer's sampling rate, i.e. mainly those that deal with sound.

In [[Standard ML]], the tilde is used as the prefix for negative numbers and as the unary negation operator.

In [[OCaml]], the tilde is used to specify the label for a labeled parameter.

In [[R (programming language)|R]], the tilde operator is used to separate the left- and right-hand sides in a model formula.<ref>[https://cran.r-project.org/doc/manuals/r-release/fullrefman.pdf The R Reference Index ]</ref>

In [[Object REXX]], the twiddle is used as a "message send" symbol. For example, <code>Employee.name~lower()</code> would cause the <code>lower()</code> method to act on the object <code>Employee</code>'s <code>name</code> attribute, returning the result of the operation. <code>~~</code> returns the object that received the method rather than the result produced. Thus it can be used when the result need not be returned or when cascading methods are to be used. <code>team~~insert("Jane")~~insert("Joe")~~insert("Steve")</code> would send multiple concurrent <code>insert</code> messages, thus invoking the <code>insert</code> method three consecutive times on the <code>team</code> object.

In [[Raku (programming language)|Raku]], {{code|~~}} is used instead of {{code|1= =~}} for a [[regular expression]]. Because the dot operator is used for member access instead of {{code|->}}, [[concatenation]] is done with a single tilde.

<syntaxhighlight lang="raku">
my $concatResult = "Hello " ~ "world!";
$concatResult ~~ /<|w><[A..Z]><[a..z]>*<|w>/;

say $/; # outputs "Hello"
# the $/ variable holds the last regex match result
</syntaxhighlight>

====Keyboards====
{{See also|QWERTY#Multilingual variants}}
The presence (or absence) of a tilde engraved on the keyboard depends on the territory where it was sold. In either case, computer's system settings determine the [[keyboard mapping]] and the default setting will match the engravings on the keys. Even so, it certainly possible to configure a keyboard for a different locale than that supplied by the retailer. On American and British keyboards, the tilde is a standard keytop and pressing it produces a free-standing "ASCII Tilde". To generate a letter with a tilde diacritic requires the [[US international]] or [[UK extended]] keyboard setting.
* With US-international, the `/~ key is a [[dead key]]: pressing the {{key press|~}} key and then a letter produces the tilde-accented form of that letter. (For example, {{key press|~}}{{nbsp}}{{key press|a}} produces {{char|ã}}.) With this setting active, an ASCII tilde can be inserted with the dead key followed by the space bar, or alternatively by striking the dead key twice in a row.
* With UK-extended, the key works normally but becomes a 'dead key' when combined with [[AltGr]]. Thus {{key press|AltGr|#}} followed by a letter produces the accented form of that letter.
* With a [[Mac (computer)|Mac]] either of the Alt/[[Option key|Option]] keys function similarly.
* With [[Linux]], the [[compose key]] facility is used.
Instructions for other national languages and keyboards are beyond the scope of this article.

In the US and European [[Windows]] systems, the [[Alt code]] for a single tilde is <code>126</code>.

==== Backup filenames ====
The dominant [[Unix]] convention for naming backup copies of files is appending a tilde to the original file name. It originated with the [[Emacs]] text editor<ref>[https://www.gnu.org/software/emacs/manual/html_node/emacs/Backup-Names.html#Backup-Names Emacs Manual]</ref> and was adopted by many other editors and some command-line tools.

Emacs also introduced an elaborate numbered backup scheme, with files named {{mono|filename.~1~}}, {{mono|filename.~2~}} and so on. It didn't catch on, as the rise of [[version control]] software eliminates the need for this usage.

==== Microsoft filenames ====
The tilde was part of [[Microsoft]]'s [[filename mangling]] scheme when it extended the [[File Allocation Table|FAT]] file system standard to support long filenames for [[Microsoft Windows]]. Programs written prior to this development could only access filenames in the so-called [[8.3 filename|8.3 format]]—the filenames consisted of a maximum of eight characters from a restricted character set (e.g. no spaces), followed by a period, followed by three more characters. In order to permit these legacy programs to access files in the FAT file system, each file had to be given two names—one long, more descriptive one, and one that conformed to the 8.3 format. This was accomplished with a name-mangling scheme in which the first six characters of the filename are followed by a tilde and a digit. For example, "{{mono|Program Files}}" might become "{{mono|PROGRA~1}}".<ref>{{cite web |title=How Windows Generates 8.3 File Names from Long File Names |url=https://www.betaarchive.com/wiki/index.php?title=Microsoft_KB_Archive/142982 |publisher=Microsoft}}</ref>

The tilde symbol is also often used to prefix hidden temporary files that are created when a document is opened in Windows.{{Citation needed|date=October 2024|reason="Often" qualification should be cited}} For example, when a document "Document1.doc" is opened in Word, a file called "~$cument1.doc" is created in the same directory. This file contains information about which user has the file open, to prevent multiple users from attempting to change a document at the same time.<ref>{{Cite web |title=Description of how Word creates temporary files |url=https://support.microsoft.com/en-us/topic/description-of-how-word-creates-temporary-files-66b112fb-d2c0-8f40-a0be-70a367cc4c85 |archive-url=https://web.archive.org/web/20240919095253/https://support.microsoft.com/en-us/topic/description-of-how-word-creates-temporary-files-66b112fb-d2c0-8f40-a0be-70a367cc4c85 |archive-date=2024-09-19 |access-date=2024-10-03 |website=Microsoft Support}}</ref>
<!-- Many applications and games, Minecraft for example, use the tilde as an arbitrary shortcut key unrelated to its conventional meaning. Please do not add this kind of detail: it will be deleted. Wikipedia is not a collection of random bits'n'bobs, nor a manual. -->

===Juggling notation===
In the [[juggling notation]] system Beatmap, tilde can be added to either "hand" in a pair of fields to say "cross the arms with this hand on top". [[Mills' Mess]] is thus represented as (~2x,1)(1,2x)(2x,~1)*.<ref>{{cite web | url=http://www.jugglingdb.com/help/?id=125 | title=The Internet Juggling Database | archive-date=28 July 2005 | archive-url=https://web.archive.org/web/20050728104414/http://www.jugglingdb.com/help/?id=125 | access-date=6 November 2009}}</ref>

== See also ==

* {{Annotated link |Circumflex}}
** {{Annotated link |Caret (computing)}}
* {{Annotated link |Tittle}}
* {{Annotated link |Double tilde (disambiguation)}}
* {{Annotated link |Backtick}}
* {{Annotated link |Wave dash}}

==Notes==
{{notelist}}

== References ==
{{Reflist}}

==External links==
{{for|signing your comments on Wikipedia|Wikipedia:Signatures|selfref=y}}

{{Latin script||tilde}}
{{Common logical symbols}}
{{navbox punctuation}}

[[Category:Latin-script diacritics]]
[[Category:Punctuation]]
[[Category:Typographical symbols]]
[[Category:Greek-script diacritics]]
[[Category:Logic symbols]]
[[Category:Mathematical symbols]]
[[Category:Letters with tilde|*]]