Bracket

A bracket, as used in British English, is either of two tall fore- or back-facing punctuation marks commonly used to isolate a segment of text or data from its surroundings. Typically deployed in symmetric pairs, an individual bracket may be identified as a 'left' or 'right' bracket or, alternatively, an "opening bracket" or "closing bracket", respectively, depending on the directionality of the context. There are four primary types of brackets. In British usage they are known as round brackets (or simply brackets), square brackets, curly brackets, and angle brackets; in American usage they are respectively known as parentheses, brackets, braces, and chevrons. There are also various less common symbols considered brackets. Various forms of brackets are used in mathematics, with specific mathematical meanings, often for denoting specific mathematical functions and subformulas. Angle brackets or chevrons ⟨ ⟩ were the earliest type of bracket to appear in written English. Desiderius Erasmus Roterodamus coined the term lunula to refer to the round brackets or parentheses ( ) recalling the shape of the crescent moon (luna). 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. In 1961, ASCII contained parenthesis, 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. However, in other languages like German, if brackets enclose text in italics, they are usually also set in italics. ( and ) are called parentheses pəˈrɛnθᵻsiːz (singular parenthesis pəˈrɛnθᵻsᵻs) in American English, and "brackets" in the UK, India, Ireland, Canada, the West Indies, New Zealand, South Africa and Australia; they are also known as "round brackets", "parens" pəˈrɛnz, "circle brackets", or "smooth brackets".