Understanding the Uses of Parentheses
Parentheses—like commas, brackets, colons, and dashes—enclose a qualifying word, clause or phrase used as an explanation that clarifies, elaborate or comments upon the preceded element in a sentence Opens in new window.
A Parenthesis encloses element that is of secondary importance in writings. It can interrupt normal syntactic flow of the sentence but not necessarily affecting the sense. The parenthesis could be taken out and the surrounding elements still maintain correct grammatical sense.
Note that Parenthesis denotes the singular form, and Parentheses, the plural form.
Ways of using Parentheses
Rule #1a: Use parentheses [()] to enclose element of second importance
Use the bracket parentheses to enclose element that clarifies the surrounded elements or elements considered as a secondary thought or importance:
Commas could have been used in the first example; a colon could have been used in the second example. The use of parentheses indicates that the writer considered the information less important—almost an afterthought.
Rule #1b: Use parentheses [()] to include de-emphasize elements
Use parentheses [()] to include element that you want to de-emphasize or that wouldn't normally fit into the flow of your text but you want to include nonetheless.
If the material within parentheses appears within a sentence, do not use a capital letter or period to punctuate that material, even if the material is itself a complete sentence. (A question mark or exclamation mark, however, might be appropriate and necessary.) If the material within your parentheses is written as a separate sentence (not included within another sentence), punctuate it as if it were a separate sentence.
If the material is important enough, use some other means of including it within your text—even if it means writing another sentence. Note that parentheses tend to de-emphasize text whereas dashes tend to make element seem even more important.
Rule #1c: Parentheses Within Parentheses
Use parentheses [()] to enclose a parenthetical remark within parentheses:
Use parentheses [()] to enclose a parenthetical remark containing a term requiring parentheses:
If the words inside the parentheses are a complete sentence, the period, question mark, or exclamation point that ends the sentence goes inside the parentheses:
This is a rule with a lot of wiggle room. A complete sentence inside the parentheses is often acceptable without an enclosed period:
Take care to punctuate correctly when punctuation is required both inside and outside parentheses.
Parentheses, despite appearances, are not part of the subject.
Joe (accompanied by his trusty mutt) was always welcome.
Commas are more likely to follow parentheses than precede them.
Parenthesis Offset with Commas
When commas are used to offset a parenthesis, it keeps the focus on the surrounding text. As commas play other roles in sentences (e.g., to separate list items and to offset adverbial phrases), readers can sometimes become confused over where a parenthesis starts and ends.
Consider the following examples (where parenthesis is offset with commas) include:
- Paul, on the other hand, is considered extremely trustworthy
- House prices in Alton, which is only 25 minutes from London, are soaring.
- Mathematics, rightly viewed, possesses not only truth but supreme beauty.
Also, if a parenthesis itself contains a comma or commas, it is advisable to avoid commas to offset it.
Parenthesis Offset with Dashes
When dashes are used to offset a parenthesis, it increases the focus on the parenthesis.