Bracket#Parentheses

Angle brackets or chevrons ⟨ ⟩ were the earliest type of bracket to appear in written English. Erasmus coined the term {{lang|la|lunula}} to refer to the round brackets or parentheses ({{nbsp}}) recalling the shape of the crescent moon ({{langx|la|luna}}).{{cite book |last=Truss |first=Lynne |author-link=Lynn Truss |title=Eats, Shoots & Leaves |date=2003 |page=161 |publisher=Penguin Publishing |isbn=1592400876}}

Most typewriters only had the left and right parentheses. Square brackets appeared with some teleprinters.

Braces (curly brackets) first became part of a character set with the 8-bit code of the IBM 7030 Stretch.{{cite web |last=Bob |first=Bemer |title=The Great Curly Brace Trace Chase |url= http://www.bobbemer.com/BRACES.HTM |access-date=5 September 2009 |archive-url= https://web.archive.org/web/20090903184346/http://www.bobbemer.com/BRACES.HTM |archive-date=3 September 2009}}

In 1961, ASCII contained parentheses, square, and curly brackets, and also less-than and greater-than signs that could be used as angle brackets.

In English, typographers mostly prefer not to set brackets in italics, even when the enclosed text is italic.{{cite book |first=Robert |last=Bringhurst |title=The Elements of Typographic Style |at=§5.3.2}} However, in other languages like German, if brackets enclose text in italics, they are usually also set in italics.{{cite book |last1=Forsmann |first1=Friedrich |last2=DeJong |first2=Ralf |date=2004 |title=Detailtypografie |trans-title=Detail Typography |language=de |location=Mainz |publisher=Herrmann Schmidt |page=263 |isbn=9783874396424}}

{{redirect-several|Parenthesis|Paren|Parens|( )}}

{{Technical reasons|:)|the keyboard symbols|List of emoticons|the generic smiling face|Smiley}}

{{Technical reasons|:(|the keyboard symbols|List of emoticons|the generic frowning face|Frown}}

{{original research|section|date=March 2022}}

{{Infobox punctuation mark

|name = Parenthesis

|variant1 = ( )

|caption1 = {{ubl|parentheses (AE)|brackets (BE)|round brackets (BE){{sfn|Pointon|Clark|2014|p=406}}}}

|unicode_list =

}}

{{Wiktionary|parenthesis|round bracket|( )|(|)}}

{{char|(}} and {{char|)}} are parentheses {{IPAc-en|p|ə|ˈ|r|ɛ|n|θ|ᵻ|s|iː|z}} (singular parenthesis {{IPAc-en|p|ə|ˈ|r|ɛ|n|θ|ᵻ|s|ᵻ|s}}) in American English, and either round brackets or simply brackets in British English.{{sfn|Pointon|Clark|2014|p=406}}{{sfn|Peters|2007|p=101}}

They are also known as "parens" {{IPAc-en|p|ə|ˈ|r|ɛ|n|z}}, "circle brackets", or "smooth brackets".

In formal writing, "parentheses" is also used in British English.{{Citation needed|date=November 2023}}

Parentheses contain adjunctive material that serves to clarify (in the manner of a gloss) or is aside from the main point.{{cite web |last1=Straus |first1=Jane |author1-link=Jane Straus |last2=Kaufman |first2=Lester |title=Parentheses—Punctuation Rules |url=https://www.grammarbook.com/punctuation/parens.asp |work=The Blue Book of Grammar and Punctuation |publisher=Jossey Bass |access-date=18 April 2014 |archive-date=19 April 2014 |archive-url=https://web.archive.org/web/20140419025523/http://www.grammarbook.com/punctuation/parens.asp |url-status=live}}

A comma before or after the material can also be used, though if the sentence contains commas for other purposes, visual confusion may result. A dash before and after the material is also sometimes used.

Parentheses may be used in formal writing to add supplementary information, such as "Senator John McCain (R - Arizona) spoke at length". They can also indicate shorthand for "either singular or plural" for nouns, e.g. "the claim(s)". It can also be used for gender-neutral language, especially in languages with grammatical gender, e.g. "(s)he agreed with his/her physician" (the slash in the second instance, as one alternative is replacing the other, not adding to it).

Parenthetical phrases have been used extensively in informal writing and stream of consciousness literature. Examples include the southern American author William Faulkner (see Absalom, Absalom! and the Quentin section of The Sound and the Fury) as well as poet E. E. Cummings.

Parentheses have historically been used where the em dash is currently used in alternatives, such as "parenthesis)(parentheses". Examples of this usage can be seen in editions of Fowler's Dictionary of Modern English Usage.

Parentheses may be nested (generally with one set (such as this) inside another set). This is not commonly used in formal writing (though sometimes other brackets [especially square brackets] will be used for one or more inner set of parentheses [in other words, secondary {or even tertiary} phrases can be found within the main parenthetical sentence]).

A parenthesis in rhetoric and linguistics refers to the entire bracketed text, not just to the enclosing marks used (so all the text in this set of round brackets may be described as "a parenthesis").{{cite dictionary |entry=Parenthesis |dictionary=The Oxford Dictionary of English Grammar |edition=2 |date=2014 |first=Bas |last=Aarts |publisher=Oxford University Press |isbn=978-0-191-74444-0}} Taking as an example the sentence "Mrs. Pennyfarthing (What? Yes, that was her name!) was my landlady.", the explanatory phrase between the parentheses is itself called a parenthesis. Again, the parenthesis implies that the meaning and flow of the bracketed phrase is supplemental to the rest of the text and the whole would be unchanged were the parenthesized sentences removed. The term refers to the syntax rather than the enclosure method: the same clause in the form "Mrs. Pennyfarthing{{snd}}What? Yes, that was her name!{{snd}}was my landlady" is also a parenthesis.{{cite dictionary |entry=Parenthesis |dictionary=The Concise Oxford Dictionary of Linguistics |edition=3 |date=2014 |first=P. H. |last=Matthews |publisher=Oxford University Press |isbn=978-0-191-75306-0}} (In non-specialist usage, the term "parenthetical phrase" is more widely understood.{{cite dictionary |entry=parenthetical |entry-url=http://www.thefreedictionary.com/parenthetical |title=The Free Online Dictionary |access-date=13 February 2013 |archive-date=6 June 2011 |archive-url=https://web.archive.org/web/20110606122628/http://www.thefreedictionary.com/parenthetical |url-status=live}})

In phonetics, parentheses are used for indistinguishableIPA Handbook p. 175 or unidentified utterances. They are also seen for silent articulation (mouthing),IPA Handbook p. 191 where the expected phonetic transcription is derived from lip-reading, and with periods to indicate silent pauses, for example {{IPA|(...)}} or {{IPA|(2 sec)}}.

An unpaired right parenthesis is often used as part of a label in an ordered list, such as this one:

{{blockquote|

a) educational testing,

b) technical writing and diagrams,

c) market research, and

d) elections.}}

Traditionally in accounting, contra amounts are placed in parentheses. A debit balance account in a series of credit balances will have parenthesis and vice versa.

{{Main|Glossary of mathematical symbols#Parentheses|Bracket (mathematics)}}

Parentheses are used in mathematical notation to indicate grouping, often inducing a different order of operations. For example: in the usual order of algebraic operations, {{math|4 × 3 + 2}} equals 14, since the multiplication is done before the addition. However, {{math|4 × (3 + 2)}} equals 20, because the parentheses override normal precedence, causing the addition to be done first. Some authors follow the convention in mathematical equations that, when parentheses have one level of nesting, the inner pair are parentheses and the outer pair are square brackets. Example:

{{bi|$[4\; \backslash times\; (3\; +\; 2)]^2\; =\; 400.$}}

Parentheses are included in the syntaxes of many programming languages. Typically needed to denote an argument; to tell the compiler what data type the Method/Function needs to look for first in order to initialise. In some cases, such as in LISP, parentheses are a fundamental construct of the language. They are also often used for scoping functions and operators and for arrays. In syntax diagrams they are used for grouping, such as in extended Backus–Naur form.

In Mathematica and the Wolfram language, parentheses are used to indicate grouping{{snd}}for example, with pure anonymous functions.

If it is desired to include the subgenus when giving the scientific name of an animal species or subspecies, the subgenus's name is provided in parentheses between the genus name and the specific epithet.{{cite web |publisher=International Commission on Zoological Nomenclature |title=Names of subgenera |url=https://code.iczn.org/chapter-2-the-number-of-words-in-the-scientific-names-of-animals/article-6-interpolated-names/?frame=1 |website=International Code of Zoological Nomenclature |access-date=6 June 2021 |year=2012 |edition=4th |archive-date=7 June 2021 |archive-url=https://web.archive.org/web/20210607005720/https://code.iczn.org/chapter-2-the-number-of-words-in-the-scientific-names-of-animals/article-6-interpolated-names/?frame=1 |url-status=live}} For instance, Polyphylla (Xerasiobia) alba is a way to cite the species Polyphylla alba while also mentioning that it is in the subgenus Xerasiobia.{{cite book |last1=Welter-Schultes |first1=Francisco W. |title=Guidelines for the Capture and Management of Digital Zoological Names Information |date=March 2013 |publisher=Global Biodiversity Information Facility |location=Copenhagen |isbn=9788792020444 |url=http://www.gbif.org/document/80625 |chapter=1.4.5.4 Species |pages=14–15}} There is also a convention of citing a subgenus by enclosing it in parentheses after its genus, e.g., Polyphylla (Xerasiobia) is a way to refer to the subgenus Xerasiobia within the genus Polyphylla.{{cite book |last1=Welter-Schultes |first1=Francisco W. |title=Guidelines for the Capture and Management of Digital Zoological Names Information |date=March 2013 |publisher=Global Biodiversity Information Facility |location=Copenhagen |isbn=9788792020444 |url=http://www.gbif.org/document/80625 |chapter=1.4.5.3 Genera |page=14}} Parentheses are similarly used to cite a subgenus with the name of a prokaryotic species, although the International Code of Nomenclature of Prokaryotes (ICNP) requires the use of the abbreviation "subgen". as well, e.g., Acetobacter (subgen. Gluconoacetobacter) liquefaciens.{{cite journal |editor1-last=Parker |editor1-first=Charles T. |editor2-last=Tindall |editor2-first=Brian J. |editor3-last=Garrity |editor3-first=George M. |title=International Code of Nomenclature of Prokaryotes: Prokaryotic Code (2008 Revision) |journal=International Journal of Systematic and Evolutionary Microbiology |date=2019 |volume=69 |issue=1A |page=S19 |doi=10.1099/ijsem.0.000778 |pmid=26596770 |doi-access=free}}

Parentheses are used in chemistry to denote a repeated substructure within a molecule, e.g. HC(CH₃)₃ (isobutane) or, similarly, to indicate the stoichiometry of ionic compounds with such substructures: e.g. Ca(NO₃)₂ (calcium nitrate).

This is a notation that was pioneered by Berzelius, who wanted chemical formulae to more resemble algebraic notation, with brackets enclosing groups that could be multiplied (e.g. in 3(AlO₂ + 2SO₃) the 3 multiplies everything within the parentheses).{{sfn|Watts|1877|pp=140–141}}{{sfn|Ihde|1984|p=115}}

In chemical nomenclature, parentheses are used to distinguish structural features and multipliers for clarity, for example in the polymer poly(methyl methacrylate).{{Cite web |title=R-0.1.5 Enclosing marks |url=https://www.acdlabs.com/iupac/nomenclature/93/r93_61.htm |access-date=3 May 2023 |website=ACDLabs.com |archive-date=3 May 2023 |archive-url=https://web.archive.org/web/20230503033434/https://www.acdlabs.com/iupac/nomenclature/93/r93_61.htm |url-status=live}}

{{clear right}}

{{Infobox punctuation mark

|name = Square brackets

|variant1 = [ ]

|unicode_list =

}}

{{Wiktionary pipe|square bracket||Unsupported titles/Square brackets|[ ]|Unsupported titles/Right square bracket|[|Unsupported titles/Left square bracket|]|crotchet|}}

{{char|[}} and {{char|]}} are square brackets in both British and American English, but are also more simply brackets in the latter.{{sfn|Pointon|Clark|2014|p=406}}{{sfn|McArthur|McArthur|2005}}

An older name for these brackets is "crotchets".Smith, John. The Printer's Grammar p. 84.

Square brackets are often used to insert explanatory material or to mark where a [word or] passage was omitted from an original material by someone other than the original author, or to mark modifications in quotations.{{cite book |title=The Chicago Manual of Style |edition=15th |publisher=University of Chicago Press |date=2003 |at=§6.104}} In transcribed interviews, sounds, responses and reactions that are not words but that can be described are set off in square brackets — "... [laughs] ...".

When quoted material is in any way altered, the alterations are enclosed in square brackets within the quotation to show that the quotation is not exactly as given, or to add an annotation.{{cite book |title=California Style Manual |at=§4:59 |edition=4th}} For example: The Plaintiff asserted his cause is just, stating,

{{blockquote|[m]y causes is sic just.}}

In the original quoted sentence, the word "my" was capitalized: it has been modified in the quotation given and the change signalled with brackets. Similarly, where the quotation contained a grammatical error (is/are), the quoting author signalled that the error was in the original with "[sic]" (Latin for 'thus').

A bracketed ellipsis, [...], is often used to indicate omitted material: "I'd like to thank [several unimportant people] for their tolerance [...]"{{cite web |url= http://www.bartleby.com/68/60/960.html |first=Kenneth G. |last=Wilson |work=The Columbia Guide to Standard American English |date=1993 |title=Brackets (Square, Angle) |publisher=Columbia University Press |via=Bartleby.com |archive-url= https://web.archive.org/web/20080524214802/http://www.bartleby.com/68/60/960.html |archive-date=24 May 2008}}

Bracketed comments inserted into a quote indicate where the original has been modified for clarity: "I appreciate it [the honor], but I must refuse", and "the future of psionics [see definition] is in doubt". Or one can quote the original statement "I hate to do laundry" with a (sometimes grammatical) modification inserted: He "hate[s] to do laundry".

Additionally, a small letter can be replaced by a capital one, when the beginning of the original printed text is being quoted in another piece of text or when the original text has been omitted for succinctness— for example, when referring to a verbose original: "To the extent that policymakers and elite opinion in general have made use of economic analysis at all, they have, as the saying goes, done so the way a drunkard uses a lamppost: for support, not illumination", can be quoted succinctly as: "[P]olicymakers [...] have made use of economic analysis [...] the way a drunkard uses a lamppost: for support, not illumination." When nested parentheses are needed, brackets are sometimes used as a substitute for the inner pair of parentheses within the outer pair.{{cite book |title=The Chicago Manual of Style |edition=15th |publisher=University of Chicago Press |date=2003 |at=§6.102, §6.106}} When deeper levels of nesting are needed, convention is to alternate between parentheses and brackets at each level.

Alternatively, empty square brackets can also indicate omitted material, usually single letter only. The original, "Reading is also a process and it also changes you." can be rewritten in a quote as: It has been suggested that reading can "also change[] you".{{cite web |url= https://depts.washington.edu/engl/askbetty/changing_quotations.php |title=How to Integrate Direct Quotations into Your Writing |archive-url= https://web.archive.org/web/20210908042208/https://depts.washington.edu/engl/askbetty/changing_quotations.php |archive-date=8 September 2021 |publisher=University of Washington |date=2004 |work=Depts.Washington.edu}}

In translated works, brackets are used to signify the same word or phrase in the original language to avoid ambiguity.{{cite book |title=The Chicago Manual of Style |edition=15th |publisher=University of Chicago Press |date=2003 |at=§6.105}}

For example: He is trained in the way of the open hand [karate].

Style and usage guides originating in the news industry of the twentieth century, such as the AP Stylebook, recommend against the use of square brackets because "They cannot be transmitted over news wires."{{cite encyclopedia |editor-last=Christian |editor-first=Darrell |editor-link=openlibrary:authors/OL7512788A |editor-last2=Froke |editor-first2=Paula Marie |editor-link2=openlibrary:authors/OL8932325A |editor-last3=Jacobsen |editor-first3=Sally A. |editor-link3=Sally Jacobsen |editor-last4=Minthorn |editor-first4=David |editor-link4=openlibrary:authors/OL7512789A |encyclopedia=Associated Press Stylebook 2014 |entry=brackets [] |version=Chapter "Punctuation Guide" |entry-url= https://archive.org/details/associatedpresss2014unse_l3a7/page/289/mode/1up |edition=49th |date=2014 |publisher=Associated Press |location=New York |isbn=9780917360589 |oclc=881182354 |lccn=2002249088 |page=289}} However, this guidance has little relevance outside of the technological constraints of the industry and era.

In linguistics, phonetic transcriptions are generally enclosed within square brackets,{{cite book |title=The Chicago Manual of Style |edition=15th |publisher=University of Chicago Press |date=2003 |at=§6.107}} whereas phonemic transcriptions typically use paired slashes, according to International Phonetic Alphabet rules. Pipes (| |) are often used to indicate a morphophonemic rather than phonemic representation. Other conventions are double slashes (⫽ ⫽), double pipes (‖ ‖) and curly brackets ({ }).

In lexicography, square brackets usually surround the section of a dictionary entry which contains the etymology of the word the entry defines.

Brackets (called move-left symbols or move right symbols) are added to the sides of text in proofreading to indicate changes in indentation:

Square brackets are used to denote parts of the text that need to be checked when preparing drafts prior to finalizing a document.

Square brackets are used in some countries in the citation of law reports to identify parallel citations to non-official reporters. For example:

{{blockquote|Chronicle Pub. Co. v Superior Court (1998) 54 Cal.2d 548, [7 Cal.Rptr. 109]}}

In some other countries (such as England and Wales), square brackets are used to indicate that the year is part of the citation and parentheses are used to indicate the year the judgment was given. For example:

{{blockquote|National Coal Board v England [1954] AC 403}}

This case is in the 1954 volume of the Appeal Cases reports, although the decision may have been given in 1953 or earlier. Compare with:

{{blockquote|(1954) 98 Sol Jo 176}}

This citation reports a decision from 1954, in volume 98 of the Solicitors Journal which may be published in 1955 or later.

They often denote points that have not yet been agreed to in legal drafts and the year in which a report was made for certain case law decisions.

{{main|Glossary of mathematical symbols#Square brackets}}

Brackets are used in mathematics in a variety of notations, including standard notations for commutators, the floor function, the Lie bracket, equivalence classes, the Iverson bracket, and matrices.

Square brackets may be used exclusively or in combination with parentheses to represent intervals as interval notation.{{sfn|Achatz|Anderson|2005|pp=165–166}} For example, {{math|[0,5]}} represents the set of real numbers from 0 to 5 inclusive. Both parentheses and brackets are used to denote a half-open interval; {{closed-open|5, 12}} would be the set of all real numbers between 5 and 12, including 5 but not 12. The numbers may come as close as they like to 12, including 11.999 and so forth, but 12.0 is not included. In some European countries, the notation {{math|[5, 12[}} is also used.{{Cite web |title=Halboffenes Intervall |url=https://www.mathe-lexikon.at/mengenlehre/intervalle/halboffenes-intervall.html |access-date=2024-04-20 |website=www.mathe-lexikon.at |language=de}}{{Cite web |title=Intervall Mathe • alle Arten & Schreibweisen |url=https://studyflix.de/mathematik/intervall-mathe-4398 |access-date=2024-04-20 |website=Studyflix |language=de}} The endpoint adjoining the square bracket is known as closed, whereas the endpoint adjoining the parenthesis is known as open.{{sfn|Achatz|Anderson|2005|pp=165–166}}

In group theory and ring theory, brackets denote the commutator. In group theory, the commutator {{math|[{{mvar|g}}, {{mvar|h}}]}} is commonly defined as {{math|{{mvar|g}}⁻¹ {{mvar|h}}⁻¹ {{mvar|g}} {{mvar|h}} }}. In ring theory, the commutator {{math|[{{mvar|a}}, {{mvar|b}}]}} is defined as {{math|{{mvar|a}} {{mvar|b}} − {{mvar|b}} {{mvar|a}} }}.

Square brackets can also be used in chemistry to represent the concentration of a chemical substance in solution and to denote charge a Lewis structure of an ion (particularly distributed charge in a complex ion), repeating chemical units (particularly in polymers) and transition state structures, among other uses.

Brackets are used in many computer programming languages, primarily for array indexing. But they are also used to denote general tuples, sets and other structures, just as in mathematics. There may be several other uses as well, depending on the language at hand. In syntax diagrams they are used for optional portions, such as in extended Backus–Naur form.

Double brackets (or white square brackets or Scott brackets), ⟦ ⟧, are used to indicate the semantic evaluation function in formal semantics for natural language and denotational semantics for programming languages.Dowty, D., Wall, R. and Peters, S.: 1981, Introduction to Montague semantics, Springer.{{cite book |last1=Scott |first1=D. |last2=Strachey |first2=C. |date=1971 |title=Toward a Mathematical Semantics for Computer Languages |publisher=Oxford University Computing Laboratory, Programming Research Group}} In the Wolfram Language, double brackets, either as iterated single brackets ({{not a typo|[[}}) or ligatures (〚) are used for list indexing.{{cite web |publisher=Wolfram Research |title=Part, Wolfram Language function |work=Reference.Wolfram.com |date=2014 |orig-year=1988 |url= https://reference.wolfram.com/language/ref/Part.html |archive-url= https://web.archive.org/web/20230331205319/https://reference.wolfram.com/language/ref/Part.html |archive-date=31 March 2023 |quote=In StandardForm and InputForm, expr{{brackets|spec}} can be input as expr〚spec〛.}}

The brackets stand for a function that maps a linguistic expression to its "denotation" or semantic value. In mathematics, double brackets may also be used to denote intervals of integers or, less often, the floor function. In papyrology, following the Leiden Conventions, they are used to enclose text that has been deleted in antiquity.{{Cite web |url= http://papyri.info/docs/leiden_plus#leiden-double-square-brackets-- |website=Papyri.info |title=Text Leiden+ Documentation |access-date=5 March 2020 |archive-date=24 February 2020 |archive-url= https://web.archive.org/web/20200224062541/http://papyri.info/docs/leiden_plus#leiden-double-square-brackets-- |url-status=live}}

{{Wiktionary|【 】}}

Some East Asian languages use lenticular brackets {{Char|【}} {{Char|】}}, a combination of square brackets and round brackets called {{linktext|lang=zh|方頭括號}} (fāngtóu kuòhào) in Chinese and {{lang|ja|

隅付き括弧}} (sumitsuki kakko) in Japanese. They are used in titles and headings in both Chinese{{citation |title=GB/T 15834-2011 标点符号用法 (General rules for punctuation) |date=10 December 2011 |at=4.9.3.3, 4.9.3.5}} and Japanese. On the Internet, they are used to emphasize a text. In Japanese, they are most frequently seen in dictionaries for quoting Chinese characters and Sino-Japanese loanwords.

{{Infobox punctuation mark

|name = Floor and ceiling

|variant1 = ⌈ceiling⌉

|variant2 = ⌊floor⌋

|unicode_list =

}}

{{Wiktionary|⌊ ⌋|⌈ ⌉}}

The floor corner brackets {{char|⌊}} and {{char|⌋}}, the ceiling corner brackets {{char|⌈}} and {{char|⌉}} (U+2308, U+2309) are used to denote the integer floor and ceiling functions.

The Quine corners {{char|⌜}} and {{char|⌝}} have at least two uses in mathematical logic: either as quasi-quotation, a generalization of quotation marks, or to denote the Gödel number of the enclosed expression.

Half brackets are used in English to mark added text, such as in translations: "Bill saw ⸤her⸥".

In editions of papyrological texts, half brackets, ⸤ and ⸥ or ⸢ and ⸣, enclose text which is lacking in the papyrus due to damage, but can be restored by virtue of another source, such as an ancient quotation of the text transmitted by the papyrus.M.L. West (1973) Textual Criticism and Editorial Technique (Stuttgart) 81. For example, Callimachus Iambus 1.2 reads: ἐκ τῶν ὅκου βοῦν κολλύ⸤βου π⸥ιπρήσκουσιν. A hole in the papyrus has obliterated βου π, but these letters are supplied by an ancient commentary on the poem. Second intermittent sources can be between ⸢ and ⸣. Quine corners are sometimes used instead of half brackets.

Known as "spike parentheses" ({{langx|sv|piggparenteser}}), {{code|⁅}} and {{code|⁆}} are used in Swedish bilingual dictionaries to enclose supplemental constructions.Examples may be found under the corresponding entry at :sv:Parentes.

{{clear}}

{{Infobox punctuation mark

|name = Curly brackets

|variant1 = { }

|unicode_list =

}}

{{char|{}} and {{char|}}} are curly brackets or braces in both American and British English.{{sfn|Pointon|Clark|2014|p=406}}{{sfn|McArthur|McArthur|2005}}

File:Curly Bracket Notation.png

Curly brackets are used by text editors to mark editorial insertions{{cite book |url=https://books.google.com/books?id=ypA27dtL0-oC&pg=PA6 |page=6 |title=Medieval Hebrew Poetry in Muslim Egypt: The Secular Poetry of the Karaite Poet Moses Ben Abraham Dar'i |series=Karaite Texts and Studies |volume=3 |editor1-first=Joachim J.M.S. |editor1-last=Yeshaya |publisher=Brill |year=2010 |isbn=9789004191303}} or interpolations.{{cite book |url=https://books.google.com/books?id=9yG9ZB0waQsC&pg=PA1053 |page=1053 |title=Textual Evidence and Commentary |volume=5 |series=The Collected Poetry of Robinson Jeffers |editor1-first=Tim |editor1-last=Hunt |publisher=Stanford University Press |year=1988 |isbn=9780804738170}}

Braces used to be used to connect multiple lines of poetry, such as triplets in a poem of rhyming couplets,{{cite book |url=https://books.google.com/books?id=0eRtOqjNMxEC&pg=PA122 |page=122 |title=The Poetry Handbook |first=John |last=Lennard |edition=2 |publisher=Oxford University Press |location=Oxford |year=2006 |isbn=9780191532733}} although this usage had gone out of fashion by the 19th century.{{sfn|Robertson|1785|p=143}}{{sfn|Wilson|1850|p=165}}

Another older use in prose was to eliminate duplication in lists and tables.{{sfn|Wilson|1850|p=165}}

Two examples here from Charles Hutton's 19th century table of weights and measures in his A Course of Mathematics:

cellpadding=0; cellspacing=0; |+ In this kingdom{{sfn|Hutton|1836|p=18}}
rowspan="5" | The standard of ...	rowspan="5" style="vertical-align:middle" | ⎧ ⎪ ⎨ ⎪ ⎩	Length is a Yard.
Surface is a Square Yard, the {{frac|1|4840}} of an Acre.
⎰ Solidity is a Cubic Yard.
⎱ Capacity is a Gallon.
Weight is a Pound.

cellpadding=0; cellspacing=0; |+ Imperial measure of CAPACITY for coals, culm, lime, fish, potatoes, fruit,– and other goods commonly sold by heaped measure:{{sfn|Hutton|1836|p=20}}
2 Gallons	= 1 Peck	= 764	⎱ | rowspan = "2" | Cubic Inches, nearly
8 Gallons	= 1 Bushel	= {{frac|2813|1|2}}	⎰
3 Bushels	= 1 Sack	= {{frac|4|8|9}}	⎱ | rowspan = "2" | Cubic Feet, nearly
12 Sacks	= 1 Chald.	= {{frac|58|2|3}}	⎰

As an extension to the International Phonetic Alphabet (IPA), braces are used for prosodic notation.

In music, they are known as "accolades" or "braces", and connect two or more lines (staves) of music that are played simultaneously.{{cite web |url= http://www.decodeunicode.org/u%2B007B |title=U+007B LEFT CURLY BRACKET |website=DecodeUnicode.org |access-date=3 May 2009 |archive-url= https://web.archive.org/web/20081202121802/http://www.decodeunicode.org/u%2B007B |archive-date=2 December 2008}}

The use of braces in chemistry is an old notation that has long since been superseded by subscripted numbers.{{sfn|Watts|1877|pp=140–141}}

The chemical formula for water, H₂O, was represented as $\backslash left\; .\; \{\{H\}\backslash atop\{H\}\}\; \backslash right\; \backslash \}\; O$.{{sfn|Watts|1877|pp=140–141}}

{{clear left}}

{{See also|Bracing style}}

In many programming languages, curly brackets enclose groups of statements and create a local scope. Such languages (C, C#, C++ and many others) are therefore called curly bracket languages.{{cite web|url= http://www.riedquat.de/prog/style |title=Brace and Indent Styles and Code Convention |work=Programming with Style |via=Riedquat.de |archive-url= https://web.archive.org/web/20150924070732/http://www.riedquat.de/prog/style |archive-date=24 September 2015}} They are also used to define structures and enumerated type in these languages.

In various Unix shells, they enclose a group of strings that are used in a process known as brace expansion, where each successive string in the group is interpolated at that point in the command line to generate the command-line's final form.{{sfn|Newham|Rosenblatt|1998|p=14}}

The mechanism originated in the C shell and the string generation mechanism is a simple interpolation that can occur anywhere in a command line and takes no account of existing filenames.{{sfn|Sobell|Seebach|2005|p=323}}

In syntax diagrams they are used for repetition, such as in extended Backus–Naur form.

In the Z formal specification language, braces define a set.

{{main|Glossary of mathematical symbols#Braces}}

In mathematics they delimit sets, in what is called set notation.{{sfn|Biggs|2002}}

Braces enclose either a literal list of set elements, or a rule that defines the set elements.{{sfn|Biggs|2002}}

For example:

• {{math|1=S = {{{mvar|a}}, {{mvar|b}}}}} defines a set {{mvar|S}} containing {{mvar|a}} and {{mvar|b}}.{{sfn|Biggs|2002}}
• {{math|1=S = {{{mvar|x}} | {{mvar|x}} > 0}}} defines a set {{mvar|S}} containing elements (implied to be numbers) {{math|{{mvar|x}}₀}}, {{math|{{mvar|x}}₁}}, and so on where every {{math|{{mvar|x}}_{{mvar|n}}}} satisfies the rule that it is greater than zero.{{sfn|Biggs|2002}}

They are often also used to denote the Poisson bracket between two quantities.

In ring theory, braces denote the anticommutator where {{math|{{{mvar|a}}, {{mvar|b}}}}} is defined as {{math|{{mvar|a}} {{mvar|b}} + {{mvar|b}} {{mvar|a}} }}.

{{Wiktionary pipe|curly bracket||brace||Unsupported titles/Curly brackets|{ }|Unsupported titles/Right curly bracket|{|Unsupported titles/Left curly bracket|}|squiggly||accolade|}}

{{clear}}

{{Redirect|Angle bracket|a mechanical part used for joining|Angle bracket (fastener)}}

{{More citations needed section|date=November 2012}}

{{Infobox punctuation mark

|name = Angle brackets

|variant1 = ⟨ ⟩

|caption1 = Angle brackets (BE&AE){{sfn|Pointon|Clark|2014|p=406}}

|variant2 = ⟪ ⟫

|caption2 = Angle brackets (BE&AE){{sfn|Pointon|Clark|2014|p=406}}

|variant3 = < >

|caption3 = less-than and greater-than

|unicode_list =

}}

The symbols {{char|⟨}} and {{char|⟩}} are angle brackets in both American and British English.{{sfn|Pointon|Clark|2014|p=406}}{{sfn|McArthur|McArthur|2005}} In (largely archaic) computer slang, they were sometimes known as "brokets".{{cite web |url= http://catb.org/jargon/html/B/broket.html |title=broket |work=The Jargon File |edition=ver. 4.4.7 |last1=Raymond |first1=Eric S. |via=CatB.org |access-date=13 February 2013 |archive-date=10 February 2013 |archive-url= https://web.archive.org/web/20130210033248/http://www.catb.org/jargon/html/B/broket.html |url-status=live}}

Strictly speaking they are distinct from V-shaped chevrons, as they have (where the typography permits it) a broader span than chevrons,{{sfn|Peters|2007|p=138}} although when printed often no visual distinction is made.{{sfn|Peters|2007|p=101}}

The ASCII less-than and greater-than characters {{char|<}} and {{char|>}} are often used for angle brackets. In many cases, only those characters are accepted by computer programs, and the Unicode angle brackets are not recognized (for instance, in HTML tags). The characters for "single" guillemets ({{char|‹}} and {{char|›}}) are also often used, and sometimes normal guillemets ({{char|«}} and {{char|»}}) when nested angle brackets are needed.

The angle brackets or chevrons {{unichar|27E8}} and {{unichar|27E9}} are for mathematical use and Western languages, whereas {{unichar|3008}} and {{unichar|3009}} are for East Asian languages. The chevrons at U+2329 and U+232A are deprecated in favour of the U+3008 and U+3009 East Asian angle brackets. Unicode discourages their use for mathematics and in Western texts, because they are canonically equivalent to the CJK code points U+300n and thus likely to render as double-width symbols. The less-than and greater-than symbols are often used as replacements for chevrons.

{{notelist|refs=

&lang; and &rang; were tied to the deprecated symbols U+2329 and U+232A in HTML4 and MathML2, but are being migrated to U+27E8 and U+27E9 for HTML5 and MathML3, as defined in [http://www.w3.org/TR/xml-entity-names/#diff-xhtml1 XML Entity Definitions for Characters] ({{Webarchive|url= https://web.archive.org/web/20130127173609/http://www.w3.org/TR/xml-entity-names/#diff-xhtml1 |date=27 January 2013}}).

}}

Angle brackets are larger than less-than and greater-than signs, which in turn are larger than guillemets.

File:Angle brackets and less+greater signs and half guillemets in different fonts.svgs in fonts Cambria, DejaVu Serif, Andron Mega Corpus, Andika and Everson Mono]]

{{clear left}}

Angle brackets are infrequently used to denote words that are thought instead of spoken, such as:

:{{angbr|What an unusual flower!}}

In textual criticism, and hence in many editions of pre-modern works, chevrons denote sections of the text which are illegible or otherwise lost; the editor will often insert their own reconstruction where possible within them.{{cite book |last1=Trask |first1=Robert Lawrence |title=The Dictionary of Historical and Comparative Linguistics |date=2000 |publisher=Edinburgh University Press |page=22 |chapter-url=https://books.google.com/books?id=EHeGzQ8wuLQC&pg=PA22 |chapter=Angle brackets |isbn=9781579582180 |access-date=8 August 2015 |archive-date=31 October 2023 |archive-url=https://web.archive.org/web/20231031135122/https://books.google.com/books?id=EHeGzQ8wuLQC&pg=PA22#v=onepage&q&f=false |url-status=live }}

In comic books, chevrons are often used to mark dialogue that has been translated notionally from another language; in other words, if a character is speaking another language, instead of writing in the other language and providing a translation, one writes the translated text within chevrons. Since no foreign language is actually written, this is only notionally translated.{{Citation needed|date=March 2017}}

In linguistics, angle brackets identify graphemes ({{abbr|e.g.|for example}}, letters of an alphabet) or orthography, as in "The English word {{IPA|/kæt/}} is spelled {{angbr|cat}}."{{cite book |last=Bauer |first=Laurie |title=The Linguistics Student's Handbook |date=2007 |publisher=Edinburgh University Press |page=99 |chapter-url=https://books.google.com/books?id=WsrtrmHkLvoC&pg=PA99 |chapter=Notational conventions: Brackets |isbn=9780748627592 |access-date=8 August 2015 |archive-date=31 October 2023 |archive-url=https://web.archive.org/web/20231031135124/https://books.google.com/books?id=WsrtrmHkLvoC&pg=PA99 |url-status=live }}{{cite book |last=Sampson |first=Geoffrey |editor-last=Allan |editor-first=Keith |title=The Routledge Handbook of Linguistics |date=2016 |publisher=Routledge |page=60 |chapter-url=https://books.google.com/books?id=3vssCgAAQBAJ&pg=PA60 |chapter=Writing systems: methods for recording language |isbn=9781317513049 |access-date=8 August 2015 |archive-date=31 October 2023 |archive-url=https://web.archive.org/web/20231031135126/https://books.google.com/books?id=3vssCgAAQBAJ&pg=PA60#v=onepage&q&f=false |url-status=live }} {{crossreference|(See IPA Brackets and transcription delimiters.)}}

In epigraphy, they may be used for mechanical transliterations of a text into the Latin script.

In East Asian punctuation, angle brackets are used as quotation marks. Chevron-like symbols are part of standard Chinese, Japanese and{{snd}} less frequently{{snd}} Korean punctuation, where they generally enclose the titles of books, as: 〈 ︙ 〉 or 《 ︙ 》 for traditional vertical printing — written in vertical lines — and as 〈 ... 〉 or 《 ... 》 for horizontal printing — in horizontal.

{{main|Glossary of mathematical symbols#⟨⟩}}

Angle brackets (or 'chevrons') are used in group theory to write group presentations, and to denote the subgroup generated by a collection of elements. In set theory, chevrons or parentheses are used to denote ordered pairs{{cite book |last=Hefferon |first=Jim |title=Linear algebra |edition=Third |url= http://joshua.smcvt.edu/linearalgebra/book_ed3.pdf |page=121 |publisher=Saint Michael's College |access-date=26 March 2021 |archive-date=3 December 2020 |archive-url= https://web.archive.org/web/20201203193951/http://joshua.smcvt.edu/linearalgebra/book_ed3.pdf |url-status=live}} and other tuples, whereas curly brackets are used for unordered sets.

In physical sciences and statistical mechanics, angle brackets are used to denote an average (expected value) over time or over another continuous parameter. For example:

:$\backslash left\backslash langle\; V(t)^2\; \backslash right\backslash rangle\; =\; \backslash lim\_\{T\backslash to\backslash infty\}\; \backslash frac\{1\}\{T\}\backslash int\_\{-\backslash frac\{T\}\{2\}\}^\{\backslash frac\{T\}\{2\}\}\; V(t)^2\backslash ,\{\backslash rm\{d\}\}t.$

In mathematical physics, especially quantum mechanics, it is common to write the inner product between elements as {{math|{{bra-ket|a|b}}}}, as a short version of {{math|{{bra|a}}·{{ket|b}}}}, or {{math|{{bra|a}}Ô{{ket|b}}}}, where {{math|Ô}} is an operator. This is known as Dirac notation or bra–ket notation, to note vectors from the dual spaces of the Bra {{angbr|{{math|A{{pipe}}}} and the Ket {{math|{{pipe}}B}}}}. But there are other notations used.

In continuum mechanics, chevrons may be used as Macaulay brackets.

In C++ angle brackets (actually less-than and greater-than) are used to surround arguments to templates. They are also used to surround the names of header files; this usage was inherited from and is also found in C.

In the Z formal specification language, angle brackets define a sequence.

In HTML, angle brackets (actually 'greater than' and 'less than' symbols) are used to bracket meta text. For example {{tag|b|o}} denotes that the following text should be displayed as bold. Pairs of meta text tags are required – much as brackets themselves are usually in pairs. The end of the bold text segment would be indicated by {{tag|b|c}}. This use is sometimes extended as an informal mechanism for communicating mood or tone in digital formats such as messaging, for example adding "<sighs>" at the end of a sentence.

{{Wiktionary pipe|angle bracket||⟨ ⟩||Unsupported titles/Enclosing less than greater than|< >|broket||pointy bracket||diamond bracket|}}

{{clear}}

Representations of various kinds of brackets in Unicode and their respective HTML entities, that are not in the infoboxes in preceding sections, are given below.

{{notelist|refs=

This is fullwidth version of {{unichar|2033}}. In vertical texts, {{unichar|301F}} is preferred.

These characters are not used in typical documents. Instead the respective horizontal characters are used and the character that is rendered depends on the writing direction.

The original name of this character is "Presentation Form For Vertical Right White Lenticular {{sic|Brakcet}}". Since Unicode character names cannot be changed, this character has the corrected name as an alias.

}}

• Bracket (mathematics)
• International variation in quotation marks
• Emoticon
• Japanese typographic symbols
• Order of operations
• Triple parentheses

{{Reflist|30em|refs=

{{cite web |url= https://www.unicode.org/charts/PDF/UFF00.pdf |title=Halfwidth and Fullwidth Forms Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=7 February 2016 |archive-date=22 February 2016 |archive-url= https://web.archive.org/web/20160222001703/https://www.unicode.org/charts/PDF/UFF00.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U0000.pdf |title=C0 Controls and Basic Latin Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=27 February 2016 |archive-date=26 May 2016 |archive-url= https://web.archive.org/web/20160526182105/http://www.unicode.org/charts/PDF/U0000.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U2070.pdf |title=Superscripts and Subscripts Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=27 February 2016 |archive-date=13 April 2018 |archive-url= https://web.archive.org/web/20180413025550/http://www.unicode.org/charts/PDF/U2070.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U27C0.pdf |title=Miscellaneous Mathematical Symbols-A Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=7 February 2016 |archive-date=13 April 2018 |archive-url= https://web.archive.org/web/20180413030824/http://www.unicode.org/charts/PDF/U27C0.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U2980.pdf |title=Miscellaneous Mathematical Symbols-B Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=7 February 2016 |archive-date=12 November 2018 |archive-url= https://web.archive.org/web/20181112231107/https://www.unicode.org/charts/PDF/U2980.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U3000.pdf |title=CJK Symbols and Punctuation Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=7 February 2016 |archive-date=7 April 2009 |archive-url= https://web.archive.org/web/20090407061216/http://www.unicode.org/charts/PDF/U3000.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U2700.pdf |title=Dingbats Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=7 February 2016 |archive-date=17 April 2018 |archive-url= https://web.archive.org/web/20180417062019/http://unicode.org/charts/PDF/U2700.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U2E00.pdf |title=Supplemental Punctuation Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=7 February 2016 |archive-date=24 November 2021 |archive-url= https://web.archive.org/web/20211124073722/https://www.unicode.org/charts/PDF/U2E00.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U2000.pdf |title=General Punctuation Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=1 March 2016 |archive-date=3 March 2016 |archive-url= https://web.archive.org/web/20160303175510/http://www.unicode.org/charts/PDF/U2000.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/L2/L2021/21042-phonetic%20punct.pdf |title=L2/21-042: Unicode request for phonetic punctuation & diacritics |date=11 January 2021 |first=Kirk |last=Miller |access-date=19 November 2022 |archive-date=8 October 2022 |archive-url= https://web.archive.org/web/20221008021915/http://www.unicode.org/L2/L2021/21042-phonetic%20punct.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/UFB50.pdf |title=Arabic Presentation Forms-A Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=7 February 2016 |archive-date=28 April 2014 |archive-url= https://web.archive.org/web/20140428184606/http://unicode.org/charts/PDF/UFB50.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U2300.pdf |title=Miscellaneous Technical Code Chart |work=The Unicode Standard |publisher=Unicode Consortium |access-date=7 February 2016 |archive-date=30 December 2019 |archive-url= https://web.archive.org/web/20191230040331/http://unicode.org/charts/PDF/U2300.pdf |url-status=live}}

{{cite web |url= https://www.unicode.org/charts/PDF/U2300.pdf |title=Small Form Variants|work=The Unicode Standard |publisher=Unicode Consortium}}

{{cite web |url= https://www.unicode.org/charts/PDF/UFE30.pdf|title=CJK Compatibility Forms|work=The Unicode Standard |publisher=Unicode Consortium}}

{{cite web |url= https://www.unicode.org/charts/PDF/UFE10.pdf|title=Vertical Forms|work=The Unicode Standard |publisher=Unicode Consortium}}

}}

{{refbegin}}

• {{cite book|title=Concise Oxford Companion to the English Language|chapter=Brackets|author1-first=Thomas Burns|author1-last=McArthur|author1-link=Tom McArthur (linguist)|author2-first=Roshan|author2-last=McArthur|publisher=Oxford University Press|year=2005|isbn=9780192806376}}
• {{cite book|title=Words: A User's Guide|author1-first=Graham|author1-last=Pointon|author2-first=Stewart|author2-last=Clark|publisher=Routledge|year=2014|isbn=9781317864295|chapter=Punctuation Guide}}
• {{cite book|title=The Cambridge Guide to Australian English Usage|author1-first=Pam|author1-last=Peters|author1-link=Pam Peters|edition=2nd|publisher=Cambridge University Press|year=2007|isbn=9781139465212}}
• {{cite encyclopaedia|encyclopaedia=A Dictionary of Chemistry and the Allied Branches of Other Sciences|volume=4|author1-first=Henry|author1-last=Watts|author1-link=Henry Watts (chemist)|publisher=Longmans, Green, and Company|year=1877|article=Notation}}
• {{cite book|title=Learning the Bash Shell|author1-first=Cameron|author1-last=Newham|author2-first=Bill|author2-last=Rosenblatt|publisher=O'Reilly Media|year=1998|isbn=9781565923478}}
• {{cite book|title=A Practical Guide to UNIX for Mac OS X Users|author1-first=Mark G.|author1-last=Sobell|author2-first=Peter|author2-last=Seebach|publisher=Prentice Hall Professional|year=2005|isbn=9780321629982}}
• {{cite book|title=Discrete Mathematics|author1-first=Norman|author1-last=Biggs|publisher=OUP Oxford|year=2002|isbn=9780198507178|chapter=Set notation}}
• {{cite book|title=The Development of Modern Chemistry|series=Dover Books on Chemistry|author1-first=Aaron J.|author1-last=Ihde|publisher=Courier Corporation|year=1984|isbn=9780486642352}}
• {{cite book|title=Technical Shop Mathematics|author1-first=Thomas|author1-last=Achatz|author2-first=John G.|author2-last=Anderson|editor1-first=Kathleen|editor1-last=McKenzie|publisher=Industrial Press|year=2005|isbn=9780831130862}}
• {{cite book|title=Treatise on English Punctuation|author1-first=John|author1-last=Wilson|edition=2nd|publisher=Published by the author|location=Boston|year=1850}}
• {{cite book|title=An Essay on Punctuation|author1-first=Joseph|author1-last=Robertson|author1-link=Joseph Robertson (priest)|publisher=J. Walter|location=London|year=1785}}
• {{cite book|title=A Course of Mathematics|volume=1|edition=11th|author1-first=Charles|author1-last=Hutton|author1-link=Charles Hutton|editor1-first=Olinthus|editor1-last=Gregory|publisher=Longman, Rees|location=London|year=1836}}

{{refend}}

• {{cite book |author-link=John Lennard |last=Lennard |first=John |title=But I Digress: The Exploitation of Parentheses in English Printed Verse |date=1991 |isbn=0198112475 |publisher=Clarendon Press |location=Oxford}}
• {{cite book |last1=Turnbull |first1=Arthur T. |last2=Baird |first2=Russell N. |title=The Graphics of Communication: Typography, Layout, Design |publisher=Holt, Rinehart and Winston |location=New York |date=1964}} States that what are depicted as brackets above are called braces and braces are called brackets. This was the terminology in US printing prior to computers.

• {{commons category-inline|Brackets (punctuation marks)|Brackets}}
• {{wiktionary-inline|bracket}}

{{navbox punctuation}}

Category:Punctuation

Category:Mathematical notation