Punctuation: Learn It 4

Parentheses

Parentheses can do more than make smiley faces :) and sad faces :( like these! They serve an important function in formal writing as well.

parentheses

Appropriate alternative text for this image can be found in the caption.
Figure 1. An opening and closing parentheses.

Parentheses are used to set off information in a sentence that is important but not really a part of the main message.

It’s important to remember that your sentence should make sense if you eliminate the parentheses and all that is contained between them.

Remember, parentheses always appear in pairs. If you open a parenthesis, you need another to close it!

Using Parentheses

If a full sentence is enclosed in parentheses and begins with a capital letter, the end punctuation should be placed inside the parentheses.

Typically, suppliers specify air-to-cloth ratios of 6:1 or higher. (However, ratios of 4:1 should be used for applications involving silica or feldspathic minerals.)

When parentheses appear in the middle of a sentence, punctuation is placed after the closing parenthesis, not inside.

The new filtration system is more efficient (even under high humidity conditions), but it requires regular maintenance.

Parentheses can also be used to provide acronyms or spell out full names for acronyms.

  • We use the MLA (Modern Language Association) style guide here.
  • The Modern Language Association (MLA) style guide is my favorite to use.

You’ll probably use parentheses most often in your research papers because both APA and MLA formatting require in-text citations using parentheses. So, right after a quote or any other borrowed information, you should include an in-text citation in parentheses.

When parentheses enclose a citation at the end of a sentence, the sentence’s punctuation comes after the parentheses.

Example (APA in-text citation):
“The results confirmed the hypothesis” (Jones, 2011, p. 131).Example (MLA in-text citation):
“The results confirmed the hypothesis” (Jones 131).

The period comes after the parentheses in both APA and MLA format. The exception to this rule is with block quotes. When using block quotes, in both APA and MLA format, the period comes before the in-text citation.

In technical writing, there are additional rules for using parentheses, which can be more nuanced. While we won’t discuss those rules here, it’s important to bear their existence in mind, especially if you’re considering going into a more technical field.