How and when to use parentheses and brackets can be confusing. We will look at how parentheses and brackets are used, the difference between the two, what these punctuation marks are called in British English and some examples of their use in sentences.
Parentheses set off material that is useful to the reader but is not crucial to the meaning of a sentence. Parenthetical words, phrases, and clauses are usually remarks from the writer, informative side-notes, introduced abbreviations, definitions, translations, examples, cross-references to other things within a text, or citations. If the meaning of the sentence would be clear without the parenthetical remark, then parentheses are appropriate. When a parenthetical remark contains crucial information, consider an alternative form of punctuation. In British English, parentheses are called round brackets. The singular form of parentheses is parenthesis.
Brackets are used when words are added by someone other than the original writer in order to clarify the information. Brackets are often used when clarifying the noun that a pronoun has replaced or adding missing words that will make a sentence grammatically correct. In British English, brackets are known as square brackets.
The when-pigs-fly stat of the season (so far): Washington State had 101 rushing yards (3.4 per carry) last week against Stanford, while the Cardinal had 61 yards on the ground (2.3). (The Lincoln Journal-Star)
The onewordization often happens eventually, of course, and some of those coinages make intuitive good sense (“crowdsource” is an ironic example), but the same people who get agitated when old farts like me won’t write “livestream” and “newsfeed” as solid will then turn around and refer to WordPress as “Word Press.” (The Washington Post)
And another: “Perhaps somebody will take the hint and explain [the purpose of square brackets].” (The Guardian)
While on the topic of doubt, why oh why did anyone doubt MWD’s assessment that Morry Schwartz’s The [Boring] Saturday Paper is, well, boring? (The Australian)