parentheses

Parentheses, or round brackets, are used to enclose additional information serving to explain, amplify or provide comments on adjacent material.

Commas and dashes are also used for this purpose; however, parentheses are generally used for words that are less closely related to the rest of the sentence than material which would be set off by dashes or commas.

Parentheses are also more convenient for parenthetic elements which run to some length or contain internal punctuation, although it is best to avoid lengthy parentheses wherever possible.

Clarification

Parentheses may save the writer from other punctuation problems, such as the confusion created when apposition commas and enumeration commas appear together, as illustrated below:

• Carla Tavares (a recent MBA graduate), Lisa Thompson and three students

not

• Carla Tavares, a recent MBA graduate, Lisa Thompson and three students

Punctuation with parentheses

A parenthesis consisting of a complete sentence does not take an initial capital and final period unless it stands alone between complete sentences:

• To achieve the best possible results, adopt a combination of the CPM and PERT methods. (See a model of such a combination in the attached paper.) This will provide you with an effective, low-cost control mechanism.

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 below):

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

After the closing parenthesis, any punctuation which would be appropriate in the absence of the parenthesis should still be used:

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

Before a closing parenthesis, only a period, question mark, exclamation mark or quotation mark is permitted:

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

Afterthoughts and asides

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

• The premier (no mean orator himself) was enthusiastic in his praise of the minister’s speech.

An important afterthought, however, 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.

In transcripts, use parentheses to enclose information on one of the speakers:

• The Hon. Marc Garneau (Minister of Transport):
  Mr. Speaker, I welcome the opportunity to speak on this motion.

Parentheses should not alter the flow of the sentence in which they are inserted; the rest of the sentence should make sense if the parenthetic element is removed. The following is incorrect:

• She had to forfeit her acting appointment (not to mention her bilingualism bonus) and she got no sympathy on either count.

Parentheses within parentheses

If you cannot avoid placing parenthetic material within other parenthetic material, use square brackets within the round brackets, or use a combination of parentheses and em 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.

Legal documents

In legal texts, parentheses are used to enclose numerals previously written out:

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

Letters and numerals

Individual letters or groups of letters may be enclosed within parentheses:

• Language(s) spoken in the home

Numerals or letters of enumeration may be enclosed in parentheses (or be followed by a period):

• 4. Work plan
  (a) Evaluation
  (b) Training
  
• Guidelines: (1) Be concise. (2) Write idiomatically. (3) Proofread carefully.

© Public Services and Procurement Canada, 2024
TERMIUM Plus^®, the Government of Canada's terminology and linguistic data bank
Writing tools – Writing Tips
A product of the Translation Bureau