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The Rules for Using Round and Square BracketsRound brackets are used to add information to text or to show a plural option, e.g., "add the apple(s)." Square brackets are used to clarify quoted words, usually by showing changes to the original quotation.
Table of Contents
- Three Ways to Use Round Brackets
- Two Ways to Use Square Brackets
- Round Brackets Explained in Detail
- (1) Using Round Brackets to Insert Additional Information into Text
- (2) Using Round Brackets to Introduce an Abbreviation
- (3) Using Round Brackets to Show a Plural Option
- Why Round Brackets Are Important
- Square Brackets Explained in Detail
- (1) Using Square Brackets to Show That Text in a Quotation Was Not in the Original.
- (2) Using Square Brackets to Show That Text in a Quotation Was in the Original
- Why Square Brackets Are Important
- Video Lesson on Square Brackets
- Printable Test
Three Ways to Use Round Brackets
Round brackets are used in three ways:
(1) To insert additional information into text.
- The stegosaurus (the best-known herbivorous dinosaur) had a brain the size of a ping pong ball. (The additional information is usually an expansion or clarification of whatever preceded or an afterthought.)
(2) To introduce an abbreviation.
- Neil Armstrong was selected to join the National Aeronautics and Space Administration (NASA) in 1962.
(3) To show a plural option alongside a singular one.
- Do not remove the pin(s) while the light is on.
Two Ways to Use Square Brackets
Square brackets are used in two ways:
(1) To show that text in a quotation did not feature in the original.
- (1a) Square brackets can be used to explain something in a quotation.
- Original quotation: "It is a contradiction in terms."
- Amended: "It [military intelligence] is a contradiction in terms."
- (1b) Square brackets can be used to modify a quotation.
- Original quotation: "It is a contradiction in terms."
- Amended: "[Military intelligence] is a contradiction in terms."
- (1c) Square brackets can be used to replace unnecessary text with [...] (called an ellipsis).
- Original quotation: "I don't want any yes-men around me. I want everybody to tell me the truth even if it costs them their jobs."
- Reduced: "I don't want any yes-men around me [...] even if it costs them their jobs."
(2) To show that text in a quotation did feature in the original.
- In your statement, you wrote: "I appraised [sic] him of the situation at about 4 o'clock." (This should be "apprised" not "appraised." The term sic is short for sic erat scriptum ("thus it was written").)
Round Brackets Explained in Detail
(1) Using Round Brackets to Insert Additional Information into Text
- The stegosaurus (a genus of herbivorous thyreophoran dinosaur) was predated by the allosaurus. (The round brackets insert an expansion.)
- The stegosaurus (the herbivore with tiles on its back and a spiky tail) weighed the same as a car. (The round brackets insert a clarification.)
- The plates on a stegosaurus's back were for display. (It is unlikely they had a thermoregulatory function like an elephant's ears.) (The round brackets insert an afterthought.)
(2) Using Round Brackets to Introduce an Abbreviation
- The Master of Business Administration (MBA) teaches approaches to business management.
(3) Using Round Brackets to Show a Plural Option
- Remove the sheet(s) so the air can flow freely (This avoids "sheet or sheets.")
- Please append the name of your guest(s) to the list. (This avoids "guest or guests.")
- Ensure the rod(s) is(are) aligned with the top section. (This is untidy.)
- The routine uses the output(s) of that(those) process(es). (This is almost unreadable.)
- The routine uses output of that process(es).
- Bring your A game on Monday. We're going to crack Mission (Im)possible.
- I'm calling it an (experi)mental project.
(Issue 1) Brackets are considered informal.Brackets are a great way to add additional information because they're easy to spot. This means they won't disrupt reading flow. There's a problem though. Brackets are considered informal, and lots of businesses and universities do not permit their use in formal documents. Don't worry. There's a solution. Using brackets is just one of your options for inserting additional information. You can also use commas or dashes.
- The stegosaurus, the best-known herbivorous dinosaur, had a brain the size of a ping pong ball. (Commas are an alternative to round brackets.)
- The stegosaurus – the iconic dinosaur that lived 150 million years ago – had a top speed of 5 mph. (Dashes are another alternative to round brackets.)
- A large stegosaurus could be 9 metres (29.5 feet) long and weigh 7 tons (15,432 pounds). (Everyone permits brackets for this purpose.)
(Issue 2) Uncertainty over whether a period goes inside or outside the close bracket.The big question with brackets is where to put the end punctuation, which is usually a period (full stop). Does it go inside or outside the brackets?
When using brackets, the positioning of end punctuation follows logic. Sometimes it goes outside the close bracket, and sometimes it goes inside. For example:
- She will ride a pony. (However, she will not ride a Dartmoor pony.) (The period belongs to the full sentence in the brackets.)
- She will ride a pony (but not a Dartmoor pony). (The period belongs to the main sentence, not to the text in the brackets.)
- She will ride a pony (she told me yesterday) but not a Dartmoor pony. (The text inside the brackets (i.e., the parenthesis) is a standalone sentence within another sentence. When this happens, you should, for readability, start the parenthesis with a lowercase letter and omit the period.)
- The group paid with a stolen credit card (my credit card!). (The exclamation mark belongs with my credit card, and the full stop ends the whole sentence.)
- The group paid with a stolen credit card (didn't you lose your card?). (The question mark belongs with the bracketed question, while the full stop ends the sentence.)
(Issue 3) Uncertainty with capital letters when expanding an abbreviation.When introducing an abbreviation, there's nothing to think about if the abbreviation represents the name of something (i.e., a proper noun). In other words, the expanded version is written with capital letters.
- The motto for the Federal Bureaux of Investigation (FBI) is "fidelity, bravery, integrity".
- Food crops are the most controversial genetically modified organism (GMO). (The full version of the abbreviation isn't immediately obvious.)
- The term Genetically Modified Organism (GMO) was popularized by the media not scientists. (The capital letters aren't justifiable under capitalization rules, but the definition of the abbreviation now stands out.)
Square Brackets Explained in Detail
(1) Using Square Brackets to Show That Text in a Quotation Was Not in the Original
In these examples, the original text is intact, but an explanation is inserted using square brackets.
- "Most people save all their lives and leave it [their money] to somebody else." (Actress Hedy Lamarr)
- "It [electricity] is really just organized lightning." (Comedian George Carlin)
- "Most people save all their lives and leave [their money] to somebody else."
- "[Electricity] is really just organized lightning."
- Angela Merkel believes "it's [her] damn duty and obligation to do everything possible for Europe to find a united path." (The original quotation was "It's my damn duty....")
- Quoting author Flannery O'Connor, Jason often reminded his children that "[t]he truth [did] not change according to [their] ability to stomach it." (The original quotation was "The truth does not change according to our ability to stomach it".)
- Alice Cooper famously said that "from the moment [he] leave[s] [his] house or hotel room, the public owns [him]." (This is a mess.)
- Alice Cooper famously said: "From the moment I leave my house or hotel room, the public owns me." (This is much tidier.)
- Education is the most powerful weapon [...] to change the world. (President Nelson Mandela) (The ellipsis replaces the words "which you can use".)
- Andy Warhol is the only genius [...] with an IQ of 60. (US author Gore Vidal) (The ellipsis replaces the words "I've ever known".)
(2) Using Square Brackets to Show That Text in a Quotation Was in the Original
- He claimed his statement was "appropriate and did not undermine the moral [sic] of our troops." (It should be morale not moral.)
(Reason 1) Square brackets allow you fit quotations snugly into your work.Quotations are a great way to incorporate information from other sources into your writing, and they are particularly useful for supporting arguments. Quotations carry a sense honesty and believability. They're like an impartial vote for your assertion. You can use square brackets to trim quotations fit snugly into your writing. So, chop and change away, but remember not to change the intended meaning.
(Reason 2) Slam someone with [sic].If you're ever the recipient of antagonistic correspondence that contains a writing error, you could use [sic] to slam the sender for their error.
- Antagonist: I am not adverse to change, but I will not be voting for your proposal.
- You: I'm pleased you're not adverse [sic] to change because my proposal has been approved. (The antagonist should have used "averse." Using [sic] this way fairly aggressive. Use sparingly.)
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