parenthesis
Pluralparentheses
- 1Either of a pair of curved brackets, ( and ), used to enclose explanatory or supplementary material in a text.
He typed an opening parenthesis but never got around to the closing one.
The editor moved the citation into parentheses at the end of the sentence.
Similarbracket
Note
The marks are named for what they enclose, the inserted remark. Using the word specifically for the round pair, ( and ), is mainly American. One mark is a parenthesis, and the pair is parentheses. Older printers counted it among the "points" of punctuation: John Johnson's Typographia (1824) lists it beside the virgil and the come, old names for the comma and the colon.
- 2A word, phrase, or clause inserted into a passage that is already grammatically complete, usually to explain or expand on it, and typically set off by brackets, commas, or dashes.
The biographical detail appears as a parenthesis, set off by dashes in the middle of the sentence.
Skilled speakers can insert a parenthesis without losing the thread of their argument.
Similaraside
Note
Greek supplied the picture: parénthesis meant "insertion," and Late Latin borrowed it as a grammarian's term for adding a letter to a syllable. In English the word names the inserted remark itself, not the marks around it, so a pair of commas or dashes can carry a parenthesis just as well as brackets can. Its synonym is parentheme, and the plural is parentheses.
- 3Round brackets used in mathematics and logic to group the terms affected by a common operator, or to enclose the components of a vector or the elements of a matrix.
Without a parenthesis around the sum, the multiplication applies only to the first term.
The vector's components are written inside parentheses, separated by commas.
Similarbracket
Note
In mathematics and logic the marks carry meaning rather than tone: they decide which terms an operator reaches, so 2(a + b) and 2a + b are different expressions. The same pair also encloses the components of a vector or the elements of a matrix. Removing or misplacing one can change the result, which is why the closing mark matters as much as the opening one.
- 4A digression from the main subject of a speech or piece of writing, or the practice of making digressions.
The lecture's twenty-minute parenthesis on medieval trade routes tested everyone's patience.
Their conversation drifted into a parenthesis about old friends before returning to business.
Similardigression, aside, tangent
Note
In rhetoric the word stretches from a single inserted phrase to a whole excursion away from the subject. It counts as a single detour (a long parenthesis) or names the habit itself (a speaker given to parenthesis). Letitia Elizabeth Landon uses it in Ethel Churchill (1837), and it still turns up in the screenplay of Up in the Air (2009).
Practice
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Origin
This is a learned borrowing from Late Latin parenthesis, meaning the addition of a letter to a syllable in a word, which itself came from Ancient Greek παρένθεσις (parénthesis), meaning "insertion."