Commonly Known As
Parentheses is commonly referred to as brackets, round brackets, curved brackets, oval brackets, and the like. Whereas, brackets are referred to as square brackets or crotchets.
Parentheses '( )' translates to 'alongside' or 'to place' in Greek, and is used to explain or point out to a certain phenomenon in a sentence or passage. Using parentheses doesn't change the essence of the text, a piece of text read without the parentheses must be perfectly meaningful.
Brackets '[ ]' on the other hand are used to add explanatory or referential content into a sentence or an excerpt extracted from a bigger piece of text, like a story or a dialog. Although, omitting brackets do not make a sentence grammatically wrong, they are required to provide reference from the original script.
When to Use Parentheses
Parentheses adds information to a sentence that isn't essential to the main topic of discussion. The sentence without this particular information would still sound perfectly meaningful and logical.
Let's take a quick example, The movie is very enlightening (an Oscar nominee). In this sentence, the text without the parentheses makes perfect sense; parentheses simply provides an extra bit about the main topic. It is important to note that parentheses can contain either a partial or complete sentences.
Using terminal punctuations like periods, exclamatory marks, question marks, etc., in sentences containing parentheses leads to a very common question―should they be used inside or outside the parentheses? In case parentheses contains a partial sentence, the terminal punctuation should not be included inside the parenthesis.
For example: Addiction to narcotics (specifically marijuana and cocaine) ruined the boy's life. The sentence above contains a partial sentence in the parentheses, and therefore, the period is used at the end (outside the parentheses) of the sentence, and not inside the parentheses.
However, if parentheses consists of a whole sentence, then the terminal punctuation should be used before the closing parenthesis.
Let's consider a few examples.
- He was convicted for murdering Mr. Stockholm (the weapon used by the assailant was a silenced Smith & Wesson 9mm.) and infiltrating the weapons facility.
- I failed! (How is it possible?) I had studied very hard for this exam.
- The movie is very enlightening. (I watched it twice.)
What about commas? Should they come before or after parentheses? Commas should necessarily follow parentheses and not precede them. For example: Although Ronald likes beef burgers (accompanied with fries and beer), he has a severe allergy to beef.
Using single inverted commas in parentheses is acceptable; check out an example. Zeugma (derived from the ancient Greek word zeûgma, which means 'yoking together') is a figure of speech which employs a single word or phrase that connects different parts of a sentence.
When to Use Brackets
Brackets, unlike parentheses, are more crucial in terms of understanding of a sentence or excerpt. However, the latter is more commonly used than the former. Brackets are mostly used in quotations to provide reference to the context.
For instance: "He pointed a knife at Dun."; the sentence is grammatically correct; however, there is no clue about who is 'he' and 'Dun', and why is he pointing a knife at Dun.
Whereas, if the sentence would be, "He [the assassin] pointed a knife at [the senator's son] Dun."; the context becomes clearer, and the reader can easily associate the sentence with the plot. Hence, brackets solve the purpose of clarifying content without altering it in any way.
Brackets are added to explain, comment, correct, or interpolate content present in the original quotation or statement. Let's delve a bit deeper into the correct usage of brackets.
One of the purposes of using brackets, as mentioned earlier, is to add text to an original piece of content. Another purpose of using a bracket is when using parentheses within parentheses. For example: He dressed shabbily and behaved in a idiotic way (he was annoying [a weirdo!]).
Another instance where brackets come handy is when changing case of a letter. Consider movie reviews or situations where a quoted statement is rewritten. In such cases, it sometimes becomes essential to change a letter from lower case to upper case or the converse.
For instance: "[T]he Negro is still not free" was a notable phrase in Martin Luther King's popular speech [I Have a Dream] of 1963. Notice the quoted text, the original phrase was used mid-sentence and the first letter wasn't capitalized.
Also, the second bracket used hints towards a particular speech of Martin Luther King, hence allowing the reader to easily associate.
A last case in which a bracket is used is when a writer feels the need to point out a grammatical error in a quoted statement or text, which can be mistaken for a transcription error.
To achieve this purpose, an adverb sic is used. Sic means 'intentionally so written', and is used in italics with a non-italic bracket (when the surrounding text is not italic) - [sic] right after the incorrectly spelled/used word. For example: If your [sic] ready, let's do this! Here sic indicates that your is wrongly used for you're.
To quickly put both parentheses and brackets in a nutshell: Parentheses is used to provide extra information about the main topic in the statement or excerpt, whereas a bracket is used to clarify, explain, correct, or comment over a quoted statement.