Punctuation: Parentheses and Brackets

Today our punctuation discussion should clarify any confusion between two uncommon punctuation marks: parentheses and brackets. Both parentheses and brackets are used to enclose information, both appearing with mirrored opening and closing marks. Parentheses are undoubtedly more common than brackets, but when do we use each one?

Remember, parentheses look like this: ( ); brackets look like this: [ ].

Parentheses
Parentheses (which is plural for parenthesis, by the way) are used to enclose information that is not essential to the overall meaning of the sentence. If you were to take out the information within the parentheses, the sentence would still make sense without it.

• Adjectives and adverbs are both modifiers; however, we will discuss adverbs in a later chapter (see Chapter 13).
• The Eiffel Tower (in Paris) is 1,063 feet tall.
• My son climbed to the top of a tree (I can't understand why!) to collect leaves for his school project.
• Emily moved to the United States when she was 19 years old (in 2006).

Note that when you have a complete sentence within the parentheses, the end punctuation goes inside the closing parenthesis. When you have only a part of a sentence, the end punctuation goes outside the closing parenthesis.

Brackets
Brackets are used almost exactly the same way as parentheses—to enclose nonessential information. However, brackets are used specifically within a set of parentheses. A set of parentheses within another set of parentheses would be extremely confusing, so we use brackets to clarify what information belongs together.

• He always drinks water (though sometimes he prefers juice [especially orange] for lunch).

Brackets are also used to indicate editorial information, or information added by someone other than the original author. When quoting another source, you must quote the text exactly as the original author wrote it; however, if the quote is not clear, use brackets to insert clarifying information. 

• "He [George Washington] was born on February 22, 1732."
• "That moment was the last time Janet saw it [her money]."

To learn more about punctuation and other grammar topics, visit us at Nomen Global.