Definition · Plain-language
Parentheses
Parentheses ( ) — also called round brackets in British English — are paired punctuation marks that enclose extra, non-essential information within a sentence.
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What parentheses enclose
Parentheses set off material that adds to a sentence without being essential to its grammar or core meaning. This might be a clarification ("the deadline (31 March) is fixed"), an example, an aside, a definition, or a cross-reference such as "(see Chapter 4)". The defining test is that the sentence must remain complete and grammatical when the bracketed words are removed. Parentheses give the enclosed information the lowest level of emphasis among the three common ways of inserting an aside: dashes draw the most attention, commas are neutral, and parentheses quietly tuck the material away. Because they de-emphasise, they suit references, citations and minor clarifications.
Punctuation in and around parentheses
How other punctuation interacts with parentheses depends on whether the bracketed material is part of a sentence or stands alone. When parentheses enclose part of a larger sentence, end punctuation goes outside the closing bracket: "We finished early (before noon)." When the parentheses enclose a complete, standalone sentence, the full stop goes inside: "We finished early. (The weather helped.)" A comma never goes immediately before an opening parenthesis; any needed comma goes after the closing one. These rules keep the bracketed aside cleanly separated from the surrounding sentence without disrupting its punctuation.
Brackets, parentheses and overuse
British and American usage name these marks differently: in British English "brackets" usually means the round ( ) marks and these specifically are "round brackets", while square [ ] marks are "square brackets"; American English tends to call the round ones "parentheses" and reserves "brackets" for the square ones. Square brackets have a distinct job — inserting editorial clarification into a quotation, as in "he [the author] argued". A practical caution applies to all of them: heavy use of parentheses can fragment a sentence and signal that the material either belongs in the main text or should be cut. If an aside is important, commas or dashes may serve it better.
Key facts
At a glance
- Definition: paired marks ( ) enclosing non-essential, supplementary information
- British name: round brackets (square brackets are [ ])
- Test: the sentence must read correctly with the brackets removed
- Emphasis: the quietest aside — less than commas or dashes
- Punctuation: end stop outside if part of a sentence, inside if standalone
- Uses: clarifications, examples, asides, cross-references and citations
Common misconceptions
What people often get wrong
Often heard: Round brackets ( ) and square brackets [ ] mean the same thing.
Actually: They differ in job. Round brackets (parentheses) enclose a writer’s own aside; square brackets insert editorial clarification into a quotation, as in "he [Smith] argued".
Often heard: The full stop always goes inside the closing parenthesis.
Actually: It depends. If the brackets enclose part of a sentence, the full stop goes outside (…before noon). If they enclose a complete standalone sentence, it goes inside. (Like this.)
Often heard: You can put any information you like in parentheses without breaking the sentence.
Actually: Bracketed material must be non-essential. The surrounding sentence has to remain complete and grammatical when the parentheses and their contents are removed.
Going deeper
