3 Things Everyone Needs To Know About Using Parentheses

Wednesday, October 253 min read

Parentheses are little curved brackets (like this) that set off a thought within a sentence. They’re often a stylistic choice, because commas and em dashes perform similar functions, but parentheses do have a specific role and rules that apply to their usage.

Parentheses should be used when the words inside the marks are not a requirement for the sentence to make grammatical sense. In other words, you could completely remove the parenthetical statement and everything would still read OK (if a little less colorful or informative). But since we’re Word Geniuses, let’s do a deeper dive on the rules for using parentheses.

When To Use a Parenthesis

Fun fact: One single curved mark is spelled “parenthesis” (with an “i”). Two (or more) of the curved brackets together are called “parentheses” (with an “e”).

Parentheses are most commonly used to indicate an aside, digression, or commentary in writing.

We’re going to Grandma’s house today (yay!).

My teacher (Mrs. Andrews) is extremely strict.

Sam agreed to babysit for the neighbors. (I thought he hated babysitting.)

In these instances, the information isn’t essential for understanding the sentence. For example, you may not need to know Mrs. Andrews is the name of the strict teacher, because “my” already gives information about their identity. However, the phrase inside the parentheses does add a little extra detail, context, or color to the sentence.

While using parentheses to indicate a tangential thought is grammatically correct, you may want to consider other punctuation marks. A comma, colon, dash, or period can do the same job of setting off a thought but may be less jarring to read.

We’re going to Grandma’s house today — yay!

My teacher, Mrs. Andrews, is extremely strict.

Sam agreed to babysit for the neighbors. I thought he hated babysitting.

As these are mostly stylistic choices, consider how they flow within the rest of the writing. Give it a read out loud and decide which punctuation marks are appropriate in context.

How To Use Parentheses

While they may be stylistic, there are rules for their usage. Since it’s a choice to use them, it’s important to use them correctly for the most impact. If the thought inside the parentheses is a complete sentence, the period goes inside the parentheses (and the preceding sentence needs its own closing punctuation). Otherwise, the period (or exclamation point or question mark) goes outside.

I walked to the store before breakfast. (That’s when they put out the best fruit!)

That store has the best fruit (but only early in the morning).

Since the information inside the parentheses is incidental, it should be ignored in regards to subject-verb agreement. If there is a singular subject without the parenthesis, then the verb should also be singular:

Mom (and her army of little dogs) was marching down the street.

Another common use for parentheses is defining acronyms, foreign words, and technical terms. In this usage, they’re doing the same job of offering some extra information to help the reader better understand the meaning of the sentence.

She ordered le poisson (fish) at the French restaurant.

The class visited the National Aeronautics and Space Administration (NASA) facility.

How To Style Parentheses

Sometimes there are stylistic rules with the choice of using parentheses. For example, AP Style encourages writers to avoid parentheses and use commas and dashes to set off information instead. AP Style also has specific rules for writing numbers, so if, for example, you’re writing a list and want to use both words and numbers in parentheses to be extra clear, that would be outside the scope of AP Style. (But that’s OK!) Unless you’re a professional writer who needs to follow a style guide, use the parentheses rules and other grammar guidelines to communicate your information most effectively.

Parentheses can set off numbers in a sentence to make it easier to follow instructions or help highlight specific items or figures.

We need ten (10) volunteers for the carnival.

Follow these steps: (1) Go upstairs, (2) find a toy, and (3) donate it.

Parentheses may be used to show that a word can be singular or plural. This is typically done by adding an (s) to the end of the word, but other variations also work.

Please direct your question(s) to the manager.

Will your child(ren) attend the event?

Finally, parentheses are used when citing publications:

The study shows plants grow more rapidly when exposed to music (Katz, 2021).

This usage is mostly reserved for academic settings, and the exact format will depend on the required style. The most common ones are AP, Chicago, or MLA, so follow those guidelines.

Featured image credit: MundusImages/ iStock

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