• 4-minute read
• 21st November 2018

An Introduction to Brackets and Parentheses

We apologize if you clicked on this page looking for DIY advice, as the brackets we’re interested in are no use for putting up shelves. Instead, we’re looking at how brackets are used in writing.

Round Brackets (Parentheses)

The most common brackets are round brackets or parentheses.  These can be used for a variety of reasons, including the following:

• Setting non-essential information apart from the rest of the text ♦
• Adding commentary from the author or narrator’s perspective ♦
• Introducing an abbreviation after the full term ♦
• Clarifying a detail or explaining something ♦

We’ve included colors above so that you can see how each of these work in the passage below:

I saw something strange while walking home the other day (a sunny Thursday). It was a pair of brackets, just hanging there in mid-air. I circled them for some time, trying to work out whether I should tell someone (I was worried nobody would believe me). Eventually, I called Dr. Jenny Braces at New York University (NYU). She told me that the brackets would “dematerialize comprehensively after an indeterminate duration if left undisturbed” (i.e., they would go away by themselves in the end).

In addition to the above, parentheses also have special uses in some subjects, such as mathematics. And in academic writing, they are used for citations in author–date referencing systems.

Square Brackets [Box Brackets]

Square brackets are most often used to indicate a change to what an author wrote, such as when editing a quote or adding an editorial note. For example, we might use them to add a translation:

Chaucer speaks of April and its “shoures soote [sweet showers].”

Here, we have added a translation of the Middle English for clarity. Using square brackets shows the reader that this is an addition, not part of the original text by Chaucer.

Other uses include to add “[sic]” after an error in a quote or to enclose ellipses (i.e., […] ). However, the rules about these can vary, so check your style guide (if available) before doing either.

Curly Brackets {Braces} and Angle Brackets ⟨Chevrons⟩

Finally, a quick word on curly brackets and angle brackets. Both of these are rare in most types of writing, but they are very useful in certain subject areas:

• Curly brackets (or “braces”) can be used to define a set of values in mathematics or computing. They are also used in musical notation.
• Angle brackets are indicated either with ⟨chevrons⟩ or <lesser than and greater than symbols>. These have several uses in the sciences, mathematics, and linguistics. However, they are rare in most writing types.

Some other symbols are also described as “brackets” (mostly from other languages). But these are even rarer than curly and angle brackets, so most people will not need to know about them.

Summary: An Introduction to Brackets and Parentheses

There are two main types of bracket that you may need to use in your writing:

• Parentheses or round brackets are used to set apart non-essential information in writing (such as to provide an example or additional information, like here). These are the most common type of brackets.
• Box brackets or square brackets are usually used to indicate an addition to text, such as a correction to a quote or an annotation from someone who is not the author [EDITOR’S NOTE: This is correct].

In some subject areas, such as computing and math, you may also see {curly brackets} and ⟨angled brackets⟩, which have technical uses. But these are very rare in most types of writing. Hopefully, this answers your bracket-based questions! But let us know if you’d like more help.