he parenthesis is a punctuation mark, which is written or typed as an upright curved line. Two parentheses, ( ), are generally paired and used to mark off explanatory or qualifying remarks in writing. Parentheses indicate an interrupting phrase, a word group (a statement, question, or exclamation) that interrupts the flow of a sentence and can also be set off with commas or dashes.
The parenthesis is a type of bracket, which when paired with another bracket—[ ]—is used to interject text within other text. Parentheses are prevalent in mathematics, too, where they are used to set off arithmetic symbols as well as numbers, operations, and equations.
Origins of the Parenthesis
The symbols themselves first showed up in the late 14th century, with scribes using virgulae convexae (also called half moons) for a variety of purposes. By the end of the 16th century, the parenthesis (from the Latin for "insert beside") had begun to assume its modern role, as Richard Mulcaster explained in "Elementarie," which was published in 1582:
"Parenthesis is expressed by two half circles, which in writing enclose some perfit branch, as not mere impertinent, so not fullie concident to the sentence, which it breaketh, and in reading warneth us, that the words inclosed by them ar to be pronounced with a lower & quikker voice, then the words either before them or after them."
In her book "Quoting Speech in Early English," Colette Moore notes that parentheses, like other marks of punctuation, originally had both "elocutionary and grammatical" functions:
"[W]e see that whether through vocal or syntactic means, the parentheses are taken as a means to downplay the significance of the material enclosed within."
Spanning more than 400 years (Moore's book was published in 2011), both authors say essentially the same thing: Parentheses separate text that, while important in that it adds meaning, is less significant than the text that falls outside of these punctuation marks.
Purpose
Parentheses allow for the insertion of some verbal unit that interrupts the normal syntactic flow of the sentence. These are called parenthetical elements, which may also be set off by dashes. An example of parentheses in use would be:
"The students (it must be acknowledged) are a foul-mouthed
