Primarily, parentheses are used to offset text in a sentence. This is useful when you want to convey extra information that may be relevant but not necessarily integral to the meaning of the sentence. Parentheses serve multiple purposes in English, and they are implemented in pairs.
Differentiating Parentheses from Brackets and Em-Dashes
Before one can fully understand parentheses and when and how to use them properly, it’s important to fully comprehend what parentheses are not. The need for parentheses can often be confused with the need for brackets or em dashes. These other forms of punctuation also help to offset text in a sentence. However, brackets are used for specific purposes, such as inserting or altering text from a direct quote, as in the following example:
“I don’t know what [Carrie] said yesterday,” he claimed.
In this quote, the speaker did not say “Carrie.” Perhaps he said “she” or simply misspoke, leaving her name out entirely. The brackets allow the sentence to make sense to us, while still informing the reader that the speaker did not actually say Carrie’s name.
Em-dashes serve an almost identical purpose as parentheses. They offset text from a sentence. However, em-dashes are less formal and convey a more abrupt or direct tone. Take the following examples:
(1) After grabbing the last of the donuts (five in total), she headed back to her desk.
(2) After grabbing the last of the donuts—five in total—she headed back to her desk.
Example 2 grabs the reader’s attention in a more abrupt and less formal way in order to convey a particular tone.
Different Uses for Parentheses
There are quite a few ways that parentheses can and should be used. The most common use of parentheses, as stated above, is to set off text from the rest of a sentence. This offset text can be as short as a single word, or as long as multiple sentences or paragraphs. The text inside the parentheses should contain information that the writer wants to convey to the reader but is not necessarily integral to the sentence. Consider these examples:
1) Shannon ordered spaghetti with a side of garlic bread.
2) Shannon ordered spaghetti, which is her favorite dish, with a side of garlic bread.
3) Shannon ordered spaghetti (her favorite dish) with a side of garlic bread.
In example 1, the reader is simply told what Shannon ordered. We aren’t given any information regarding how she feels about it. For all we know, she could hate spaghetti. Let’s say that the writer wants the reader to know that Shannon is ordering her favorite dish but doesn’t want to create an entirely separate sentence to do so.
The writer accomplishes this in example 2. The reader now knows that spaghetti is Shannon’s favorite dish. However, the sentence, while technically correct, is a bit of a mouthful. It also makes the added information a centerpiece of the sentence. Perhaps the writer doesn’t want the reader to dwell on the extra information. This is where example 3 comes in.
In example 3, the reader gets the same information, but the sentence reads much more smoothly, and the reader doesn’t focus too heavily on the fact that spaghetti is Shannon’s favorite dish.
Using Parentheses for Abbreviations and Acronyms
Parentheses are also used for abbreviations and acronyms. In articles or other pieces of content, the writer can place an abbreviation or acronym for a company, organization, or other entity inside a pair of parentheses. This allows the writer to use only the abbreviation or acronym going forward. Look at the following example:
“The World Health Organization (WHO) recommends daily physical activity for your health.”
This is especially effective if the writer is referring to an abbreviation or acronym that the reader may not be familiar with. After placing the abbreviation or acronym in the parentheses for the first instance, it can be used alone for the remainder of the text:
“But what kind of exercise does the WHO recommend?”
Other Typical Uses for Parentheses
There are a handful of additional uses for parentheses. These include (1) numbered lists, such as the one you’re reading now, (2) time zones and area codes, and (3) to show a birth year and year of death, such as in the following example:
Martin Luther King, Jr. (1929 - 1968)
Parentheses are also necessary in citations and bibliographies. The writer can use parentheses to offset a reference to a particular source in the bibliography:
“It takes 80 gallons of maple sap to create just one gallon of maple syrup (Smith, 2004, p. 22-23).”
Implementing Parentheses Correctly
When placing parentheses in a sentence, you should “test” to make sure it’s done properly. To do this, cover up, or pretend to take out the parenthetical text. Does the sentence still make sense? If so, you likely used the parentheses correctly.
The magician (and his assistant) captivated the audience.
(2) The magician (and his assistant) were loving the applause.
Example (1) is correct. If you took out “(and his assistant)”, the sentence would read “The magician captivated the audience.” This sentence still makes sense. However, if you took the parenthetical text out of example (2), it would read, “The magician were loving the applause.” This does not work.
It’s also important to punctuate inside and around the parentheses correctly. If the text inside the parentheses is a complete sentence that can stand alone, then punctuate the text inside the parentheses. If the text inside could not stand alone, and is simply an added dependent clause, then the punctuation should go outside of the closing parenthesis.
Clara studied very hard for her exam. (She was in the library for nearly 10 hours.) She was ecstatic when she received an A.
Clara studied very hard for her exam (nearly 10 hours). She was ecstatic when she received an A.
Both of these examples are correct. In example (1), the parenthetical text can stand alone as a complete sentence. Therefore, it has its own punctuation. In example (2), the parenthetical text is a smaller phrase that cannot stand alone as a complete sentence, so the period is placed outside of the closing parenthesis, allowing it to simply be apart of the larger sentence.