Bracket

Brackets are characters or symbols that are usually inserted in pairs before and after parts of a text. This enclosure, known as bracketing, delimits the content of the parts or changes their function.

In written language, parentheses serve as punctuation marks for structuring syntactic form (see also parenthesis). A generous use of brackets is considered bad style in German writing, dashes or the resolution of nested sentences are usually preferred. In other languages, e.g. English, brackets are used more frequently.

In mathematics, parentheses express, among other things, a precedence of one arithmetic operation to be performed over others in the arithmetic sequence. For example, the result of is 5, since the calculation inside the parenthesis is performed first, while is 3, since in this case the calculation is performed from left to right. In higher mathematics, parentheses also serve many other purposes, most notably to denote arguments of a function. Curly, square, and angle brackets usually have special meanings in mathematics.

Similarly, parentheses are also used in many programming languages to group several types of program elements.

In the natural sciences, brackets are not only used for mathematical calculations. In chemistry, square brackets are used to indicate concentrations. In addition, there are also round brackets when natural constants cannot be measured exactly, but are estimated. For this purpose, another number is appended to the value of the constant in parentheses - see CODATA.

Brackets in grammar and typography

Commonly used as punctuation marks are several types of parentheses, which are almost exclusively used in pairs (i.e. as opening and closing parentheses); the English terms differ in British (BE) and American (AE) English:

An opening and closing parenthesis is always preceded by a space (unless - as here - it is followed by a punctuation mark or the parenthesis indicates alternatives, as in Kolleg(inn)en). After an opening parenthesis and before a closing parenthesis, on the other hand, there is no space. (A full stop only precedes a closing parenthesis if a complete sentence is bracketed, as here).

Round brackets

(...) : (Greek/English: parentheses [AE] or round brackets [BE]): the usual brackets used in continuous text to separate and enclose parts of sentences. Unicode: U+0028 and U+0029

Square brackets

[...] : (English: brackets [AE] or square brackets [BE]): Used, among other things, when something is to be bracketed within a bracket expression or to indicate omissions and insertions in quotations. In linguistics, phone are usually enclosed in square brackets ; examples: [ˈbaɪ̯ˌʃpiːlə] (IPA phonetic transcription); "[AE]" and "[BE]" in this paragraph, "[sic]" and "[...]". Unicode: U+005B and U+005D

Curly/curved brackets (accolades)

{…} : also called nose braces (engl.: braces [AE] or curly brackets [BE], fr. : accolades): Are rarely used to join several lines together. They have a special meaning in dictionaries, for example. Unicode: U+007B and U+007D.

Angle clamps

⟨...⟩ : also called "angle brackets"; Unicode: U+27E8 and U+27E9, respectively: see below〈...〉 in the section CJK brackets). They are rarely used. In dictionaries they have a special meaning, for example the (etymological) origin of a word is put in angle brackets, more rarely style indications in dictionaries. In linguistics, graphemes and grapheme chains are placed in angle brackets. Since these characters are missing in the ASCII character set, the ASCII characters "less than" < and "greater than" > (Unicode: U+003C and U+003E; HTML: < and > ) are often used instead. The latter are often used in electronic data processing to distinguish between name and e-mail address-for example: Max Mustermann <[email protected]>

CJK Staples

Other types of brackets are common in CJK fonts; the Unicode character standard contains the additional encodings for them.

Brackets in the International Phonetic Alphabet

Square brackets

The International Phonetic Alphabet (IPA) distinguishes the square bracket on the left "[" and the square bracket on the right "]".

In the IPA, the characters "[" and "]" indicate the beginning and end of the phonetic transcription, respectively; they have IPA numbers 901 and 902 (HTML entity [ = [ and ] = ]).

Curly/curved brackets

The curly/curly brackets in the International Phonetic Alphabet indicate the beginning or end of prosodic notation; (HTML-entities { = { and } = }).