How to Use a Bracket in Grammar

Of the fourteen different punctuation marks in English, brackets are used least often. Square brackets are the type of bracket most often called just “brackets,” but parentheses and braces are sometimes considered types of brackets.

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All About Square Brackets [ ]

Square brackets are only used within quotes or on rare occasions where you need parentheses inside parentheses.

Using Square Brackets in Quotes

Writers use brackets in academic writing to add information to a quote without changing the meaning of the sentence. This means that the writer can add words, if necessary, to make the sentence clearer or add a correction or comment to quoted material.

Normally, a quotation must be presented exactly as it was spoken or written. The square bracket allows the writer to fix mistakes, add explanatory information, change a quote to fit in a sentence, or add emphasis to a word through bold or italics. Similar to parentheses, the information in the bracket cannot alter the meaning of the quoted material.

Examples of Square Bracket Use in Grammar

You only use square brackets when absolutely necessary to help the reader understand the text. Examples of when and why to use square brackets can help you better understand the punctuation.

Example 1:

"Books used [in classes] show methods of finding information but not much information in preparation of the review." (Libutti & Kopala, 1995, p.15).

In this example, the words "in classes" do not appear in the original quotation but the writer wanted to add this information to make the sentence read more clearly.

Example 2:

“We adopt the means of nonviolence because our end is a community at peace with itself [italics added].” (Martin Luther King, Jr.)

To add emphasis to a set of words, italics were added by the writer that were not there in the original quote.

Example 3:

“China steals United States Navy research drone in international waters - rips it out of water and takes it to China in unpresidented [sic] act.”

The Latin word “sic” is often used inside brackets after a spelling or grammar error to indicate the error was part of the original quote. In this quoted President Donald Trump tweet (that was later corrected) the word “unprecedented” was originally misspelled.

Example 4:

Jen hired Mel for the movie stating, “That woman just had a certain je ne sais quoi [I don’t know what].”

The brackets inside this quote translate the French phrase “je ne sais quoi” so the reader can understand it.

Example 5:

She referenced an old book of hers (The Big Book [1976]) in her new book.

The book title is added in parentheses so the reader knows what book is being referenced. As the year of publication might also need to appear in parentheses, it is nested within the parentheses in brackets here.


Brackets By Any Other Name

There are a few different types of symbols that can technically be considered brackets. Each pair of marks has its own rules for academic use. Outside of academic writing, they may all be interchangeable with few repercussions.

Parentheses or Round Brackets ( )

The most commonly used bracket pair in English is the parentheses. This pair of round brackets is used when a writer wants to add information to a sentence that will give greater detail to the information presented. However, the information is extra, which means it can be removed without damaging the original information.

Items placed in parentheses can often be set off with commas instead. Check out these sentence examples using parentheses:

Example 1:

George Washington (the first president of the United States) gave his farewell address in 1796.

In this sentence, the information in parentheses gives additional information about George Washington.

Example 2:

NASA (National Aeronautics and Space Administration) launched its first Mars probe (Viking I) back in 1976.

In this sentence, the information in parentheses explains what NASA stands for and gives additional information about the Mars probe.

Example 3:

Task representations can sometimes differ between student and instructor (Flower, 1994) and even from novice student to more experienced student.

In this sentence, the information in parentheses is a citation for a book written in APA format. Similar types of line references are used in other citation systems as well.


Angled Brackets < >

Angled brackets have very limited use in writing and are obsolete in modern writing. The most common use for angled brackets is for placing URLs (Universal Resource Locator) into text.

Example of angled bracket use:

Fishman, Stephen M., and Lucille Parkinson McCarthy. John Dewey and the Challenge of Classroom Practice. The Practitioner Inquiry Series. New York Urbana, Ill.: Teachers College Press, National Council of Teachers of English, 1998. <>

This is an example of an old MLA citation. While MLA rules no longer require URLs to be presented due to their ever-changing status, many professors may still ask students to include the URL. If this is the case, then the web address needs to be set between a pair of angled brackets.

Braces or Curly Brackets { }

Braces, or curly brackets, have extremely limited usage and are mostly used for math, computer programming, or music. An exception to this would be if a writer wanted to create a list of items that are all equal choices. Otherwise, this punctuation mark would not be used in academic writing.

Brackets Have Purpose

Punctuation marks are a basic part of English grammar. In all of these examples, the brackets set off, add emphasis, or further explain information presented to a reader. The different brackets all have slightly different functions and limited usage in academic writing, but learning how to use a bracket in grammar is as easy as recognizing and marking the extra information in a sentence.