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Parentheses (singular parenthesis) are the curved brackets that you see in this sentence. You don’t want to clutter up your sentences with them (as they interrupt the flow), but they are great for adding and organizing information. Let’s review their main uses.

Main Uses

Setting aside information

Parentheses allow you to insert information and explanations that are less important:

In 1815, Napoleon Bonaparte escaped from the island of Elba (where he had been exiled the year before).

Dear Professor, my dog died (again), and so I cannot complete the assignment.

As you can see, the extra information can have a bearing on the rest of the sentence, but grammatically it’s not essential.

Often the work of parentheses can be done by commas or dashes. The difference is that parentheses do the least to emphasize the information. They tend to downplay the importance of what’s in brackets.

Adding citations

If you are using in-text citation (so not footnotes or endnotes), you’ll want to cite your sources in parentheses:

In A Spoonful of Sugar, Dr. Ginger Peppermint argues that cough medicines like HackAway and Phlegmatix “provide merely a placebo effect” (97).

Organizing lists

If you want to organize a list, you can add some helpful letters or numbers in brackets:

My honours thesis examines (1) the use of parentheses in colonial discourse, (2) the historical occlusion of minority groups within parenthetical remarks, and (3) the ironic subversion of imperial power by means of interruption and other parenthetical strategies.

Parentheses and other punctuation

Next, let’s see how parentheses interact with other punctuation marks.

Punctuation that is not part of the parenthetical remarks goes outside and after the parentheses. With exclamation points and question marks you have to decide which part of the sentence they belong to. Compare the following ways to write the same sentence, with various degrees of emphasis:

She said that her fingers were bruised from having nail extensions (as she kept bumping into things).

She said that her fingers were bruised from having nail extensions (as she kept bumping into things)!

She said that her fingers were bruised from having nail extensions (as she kept bumping into things!).

Finally, if an entire sentence is within brackets, there are two possibilities:

  • If the sentence in brackets is inserted in another sentence (this is a good example), then you don’t need to capitalize it or put a period after it.
  • (On the other hand, if the sentence in parentheses is all by itself, then you can place the period inside the brackets.)