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How to Use Parentheses () – Guide & Examples?

Published by at August 17th, 2021 , Revised On August 24, 2023

Parentheses enclose additional information in a sentence that is not necessary for the sentence to make sense. It provides an afterthought or explanation into a passage that is grammatically correct without it.

For example,

She finally decided (after taking time to think) that she would not take the test.

The use of parenthesis in academic writing presents technical information such as equations,  acronyms, and in-text citations.

For example,

Domestic violence in London has almost doubled over the last twenty years (James, 2017).

Types of Parenthesis

There are two types of parentheses that you should be aware of in academic writing:

  • Side-by-side parentheses
  • Parentheses within parentheses (Nested parentheses)

Side-by-side Parentheses

In some cases, you may need to use two parentheses side-by-side in a single sentence. For example, you may need to present an acronym and a citation in the same sentence. Different referencing style guides have different rules for placing two or more parenthetical elements together.

If you are using the APA style guide, you will need to separate the elements in a single set of parentheses with a semicolon.

For example,

Plan and manage projects with the critical chain project management method (CCPM; Mohamed, 2019).

Chicago referencing style accepts this method but also allows for side-by-side parenthesis if their content is entirely different. You should add a space between the two parentheses when putting them together side by side.

Harvard referencing style, on the other hand, recommends nested parentheses. While there are many permutations of this but one example is:

This study showed that A is more significant than B (but it appears not to be true in some cases, (Mike, 2011)).

Parentheses within Parentheses

If there is a need to enclose a set of parentheses within another set of parentheses, then use the square brackets for the inner component.

For Example:
Most British oil and gas companies (e.g., British Petroleum (BP)) supported the new policy.
Most British oil and gas companies (e.g., British Petroleum [BP]) supported the new policy.

In American English, the use of nested parentheses is not encouraged. On the other hand, parentheses within parentheses are acceptable in British English.

However, it is still best to avoid parentheses nesting in academic writing. Rephrase the sentence so you can just the one set of parentheses in the sentence.

Most British oil and gas companies, such as British Petroleum (BP), supported the new policy.

If you need to include a citation with a parenthetical element, the Harvard referencing guide suggests using commas instead of brackets or parentheses where possible.

Recommended – It is generally true that AAAA (but it appears not to be true in solids, Mike 2011, or semisolids, Emma 2005)

Avoid – It is generally true that AAAA (but it appears not to be true in solids (Mike 2011) or semisolids (Emma 2005))


Frequently Asked Questions

Parentheses have four main functions:

  1. Clarification: Add extra, non-essential information.
  2. Grouping: Indicate order of operations in math.
  3. Citation: Provide source details in academic writing.
  4. Emphasis: Highlight content for reader’s attention.

About Alvin Nicolas

Avatar for Alvin NicolasNicolas has a master's degree in literature and a PhD degree in statistics. He is a content manager at ResearchProspect. He loves to write, cook and run. Nicolas is passionate about helping students at all levels.