parentheses

On this page

• General information
• Guidelines for using parentheses
  • Afterthoughts and asides
  • Long parenthetical elements
  • Examples and clarifications
  • Transcripts
  • Publication information
  • Letters and numerals
• Nested parenthetical material
• Punctuation with parentheses
• Additional information

General information

Parentheses, or round brackets, are composed of an opening parenthesis and a closing parenthesis: (…). They are not be confused with square brackets: […].

Parentheses are used to enclose additional or secondary information that explains, amplifies or comments on adjacent material without changing the meaning of the sentence.

They should not alter the flow of the sentence in which they’re inserted; the rest of the sentence should make sense if the parenthetical element is removed.

Guidelines for using parentheses

Afterthoughts and asides

Parentheses de-emphasize the words they contain, which often take the form of an afterthought or aside.

• The premier (a dynamic leader himself) was enthusiastic in his praise of the minister’s speech.

Note that an important afterthought should be preceded by a dash or other mark of punctuation.

• Finally the Computer Operations Branch agreed to follow through on the auditor’s recommendations—which is what it should have done six months earlier if it had had the best interests of the organization at heart.

Long parenthetical elements

Parentheses can be used to help readers separate primary information from secondary information in sentences with long parenthetical elements, particularly when they contain internal punctuation.

• While walking through the park (which, by the way, was unusually crowded for a weekday, probably due to the beautiful weather), I noticed a group of children playing soccer.

not

• While walking through the park, which, by the way, was unusually crowded for a weekday, probably due to the beautiful weather, I noticed a group of children playing soccer.

Examples and clarifications

Parentheses are often used to enclose examples.

• Doing outdoor activities (for example, hiking, cycling and kayaking) can improve your physical fitness and mental well-being.

Parentheses can be used to enclose courtesy translations in unquoted material.

• The Fédération des communautés francophones et acadienne du Canada (Federation of Francophone and Acadian Communities of Canada) promotes the development of French-language minority communities across the country.

Parentheses also can be used to enclose abbreviations when they appear after the long form.

• Public Services and Procurement Canada (PSPC)

When an abbreviation is more widely known than the long form, parentheses can used to enclose the long form.

• PDF (portable document format)

Parentheses can also help writers avoid punctuation issues, such as the confusion created when apposition commas and enumeration commas appear together.

• Alma Tavares (a recent MBA graduate), Lisa Linson and three students will help organize the event.

not

• Alma Tavares, a recent MBA graduate, Lisa Linson and three students will help organize the event.

In the example above, the parentheses make it clear that the recent MBA graduate is Alma Tavares, not a separate person.

Transcripts

In transcripts, parentheses are used to enclose information about one of the speakers.

• The Hon. Steven MacKinnon (Leader of the Government in the House of Commons, Lib.):
  Mr. Speaker, I ask that all questions be allowed to stand.

Publication information

Parentheses are used to enclose publication information, such as an author’s name or the year a work was published.

• The study found significant improvements in cognitive function among older adults (Smith, 2020).
• The report highlights the latest findings in cancer research (National Institute of Health 15).
• In R. v. Bykovets (2024), the Supreme Court of Canada addressed privacy issues with IP addresses.

Letters and numerals

Individual letters or groups of letters may be enclosed within parentheses to indicate an alternative situation.

• Language(s) spoken in the home
• Put all the equipment in the box(es).

Letters of enumeration may be followed by a closing parenthesis or enclosed in parentheses.

• 4. Work plan
  a) Evaluation
  b) Training

or

• 4. Work plan
  (a) Evaluation
  (b) Training

Numerals of enumeration may also be enclosed in parentheses.

• Guidelines: (1) Be concise. (2) Write idiomatically. (3) Proofread carefully.

In legal texts, parentheses are used to enclose numerals that follow a number written out in words.

• one thousand nine hundred and ninety-nine (1999)

Do not use parentheses in 10-digit telephone numbers.

• 613-123-4567

not

• (613) 123-4567

Nested parenthetical material

Avoid placing parenthetical material within other parenthetical material whenever possible. But if you can’t avoid it, use square brackets within the round brackets, or use a combination of parentheses and dashes.

• He worked hard (twelve hours a day [and no bonus for overtime], seven days a week) until the task was completed.

or

• He worked hard—twelve hours a day (and no bonus for overtime), seven days a week—until the task was completed.

Punctuation with parentheses

An opening parenthesis should not be preceded by any other mark of punctuation unless the parentheses are being used to enclose numbers or letters of enumeration (see Letters and numerals above). There’s no space after the opening parenthesis.

• I am (I hope) reliably informed that a new president has been appointed.

Before a closing parenthesis, only a period, question mark, exclamation mark or quotation mark is permitted. There’s no space before the closing parenthesis.

• I have always been willing (do you not agree?) to hear both sides of the issue.

After the closing parenthesis, any punctuation which would be appropriate in the absence of the parenthesis should still be used. There’s no space between the closing parenthesis and the punctuation mark that follows.

• I am (I hope), always have been and always will be an honest judge.

A parenthesis consisting of a complete sentence takes an initial capital and final punctuation mark only when it stands alone between complete sentences. The final punctuation mark is placed before the closing parenthesis.

• To achieve the best results, adopt a combination of the Critical Path Method and Project Evaluation and Review Technique. (See a model of such a combination in the attached paper.) This will provide you with an effective, low-cost control mechanism.
• David is arriving tomorrow. (I can’t wait to see him!) Can you pick him up at the airport?

Additional information

• Closing in and trailing off: Further digressions in punctuation (Peck’s English Pointers)
• Square brackets

Quizzes

• All about parentheses