The use of parentheses is a way of incorporating additional information. This additional, or parenthetical information, must function on its own; it might consist of a word, phrase, clause, explanation or comment. Parentheses can provide valuable information or clarity when used correctly, so familiarize yourself with the “9” and “0” on the number row of your computer keyboard as a way to give a little more variety to what you write. Below are the correct uses and appropriate punctuation for parentheses.
When you incorporate supplemental information with parentheses, the sentence in which it appears must maintain its meaning without the additional information. The parenthetical information can also function as a sentence of its own with separate punctuation; in this case, the ending punctuation is placed inside the parentheses. When the the punctuation applies to the sentence as a whole, punctuation is placed outside them.
Example 1: Her little boy will turn two in March (though he already looks like he is three).
The parentheses keys are used by selecting the “shift” key and the corresponding symbol above the “9” or “0” keys on your computer keyboard. (Yes, those little partial circles are used for more than creating digital smiley faces!)
Example 2: She wanted to buy a Mustang (one of her favorite cars).
Example 3: While she wanted chocolate ice cream (very, very badly), she decided to wait.
In the first example, the parenthetical information is a complete sentence that requires its own punctuation, so the exclamation point is placed inside the parentheses. In the second example, the period applies to the entire sentence, so it is placed outside the parentheses. The third example includes an example of both; “very, very badly” requires a comma that only applies to the parenthetical information, and the comma that follows the introductory clause comes outside the parentheses because it applies to the whole sentence.
Parentheses are also used to include acronyms and dates when they are not necessary for the meaning of the sentence. See the below examples.
Acronym: The Internal Revenue Service (IRS) expects all freelancers to claim all of their earnings. (Once the initial acronym is used, it is easily used in place of the full name of the entity later in any written piece.)
Date: Her grandmother (1908 – 2007) lived a long life.
When you list something in a series, letters and numbers can prove helpful in identifying the different parts of the series. For example, you can use parentheses with both letters and numbers as the below examples show.
Example 1: She went to the store for (1) apples, (2) bananas and (3) oranges.
Example 2: Her three favorite professional sports teams include a) the Green Bay Packers, b) the Milwaukee Brewers and c) the Detroit Redwings.
In either of the above examples, the double parentheses () and the single ones ) are interchangeable, as are the use of letters or numbers.
As with anything, use care not to overuse parentheses in your writing. Variety is the spice that adds flavor to your words, so the occasional use of these as a tool can make you writing more engaging. However, overuse of parentheses often creates content that is frustrating to your readers and minimizes the positive aspects they add to what you write.