Non-essential information is not needed by the sentence, but it may help the reader.
Exits are not essential for the interstate itself, but drivers need them. Information in parentheses is not essential for the sentence, but the readers need it.
Parenthetical (from the word “parentheses”) or non-essential information is not necessary to the sentence itself. Often that is extra information needed by the reader, but not by the sentence. In this sense, parentheses may replace commas in narrative. However, parentheses should be used sparingly. Commas are more common.
Think of a sentence as an interstate highway (allowing only limited exits). To travel from Teaneck (New Jersey) to downtown San Francisco (California), you stay on the road. But to stop for gas or for food (or to sleep), you need to take some exits. Those exits are essential for the driver and the car, but not for the highway.
Information between parentheses may be necessary for the reader (like stopping for gas). The sentence itself does not need it. Look at the sentences in these paragraphs. The phrases in italics (and parentheses) are taking exits. Each sentence is complete without the italicized or non-essential phrases.
- That particular weekend (the first weekend in March), we drove separately.
- (Non-essential: explains which weekend, the first weekend in March)
- Main sentence = “That particular weekend, we drove separately.”
- She retired from teaching Adult Basic Education (ABE) classes.
- (Non-essential: explains the references to ABE later in the article)
- Main sentence = “She retired from teaching Adult Basic Education classes.”
- After retiring, we went to the mountains every other week (Monday through Saturday).
- (Non-essential: explains which days of the week we went to the mountains)
- Main sentence = “After retiring, we went to the mountains every other week.
- We went to the beach once a month (usually on a weekend).
- (Non-essential: explains when we went to the beach)
- Main sentence = “We went to the beach once a month.
- Probably the most famous cigar smoker was George Burns (1896–1996).
- (Non-essential: explains the year he was born and the year he died)
- Main sentence = “Probably the most famous cigar smoker was George Burns.”
- Do you recall previous presidents using POTUS (President of the United States)?
- (Non-essential: explains the acronym “POTUS”)
- Main sentence = “Do you recall previous presidents using POTUS?
If what is in the parentheses is a complete sentence, apart from the main sentence, it is entitled to its own period inside the closing parenthesis.
- Susie had packed everything before we arrived. (She even had the cat in its carrier.) Obviously, she was eager to go.
- (The parentheses imply that the cat being in the carrier will not be important to the story later on.)
- We had allowed an extra hour to pack everything before we left. (Don’t tell Susie that is why we sat at the airport for an extra sixty minutes.)
- (The comment about telling Susie is only a side note, not important to the story.)
If the parentheses containing an explanatory word or phrase ends the sentence, the ending punctuation follows the closing parenthesis.
- We planned to spend the weekend in Springfield (not the one in Illinois).
- (“not the one in Illinois” clarifies, in case the reader did not know, which Springfield.)
- Was the plane late when it took off at 7:18 (MDT)?
- (The period follows the time zone in parentheses.)
When a complete sentence occurs inside the parentheses and within the sentence, the first letter is NOT capitalized and the inside sentence does not end with a period. A question mark or an exclamation mark may be come before the closing parenthesis. The ending period follows the closing parenthesis.
- The crew could have arrived earlier (it seemed to me) for us to leave on time (but we didn’t).
- (No capital letter to begin “it seemed to me” or “but we didn’t.”)
- (The period before the closing quotation mark here follows a complete sentence is inside the closing quotation mark, which is inside the closing parenthesis.)
- (No period for either sentence in parentheses.)
- (The period follows the last closing parenthesis.)
- (No capital letter to begin “it seemed to me” or “but we didn’t.”)
- The explanation (there was an accident on the highway) seemed logical (don’t you think?).
- (The sentence inside either pair parentheses begins with a lower-case letter.)
- (The period at the end of the sentence follows the closing parenthesis, which follows the question mark following the question.
If what comes before the parentheses would normally have a punctuation (i.e., a comma) after it, the punctuation follows the closing parenthesis.
- If the crew had arrived earlier (it seemed to me), we would have left on time.
- (The comma that would have followed “earlier” now follows the closing parenthesis of “it seemed to me”.)
- We arrived on time (8:32), so the pilot must have put his foot to the floor.
- (The comma that would have followed “on time,” now follows the closing parenthesis of the time they arrived.)
Because the United States covers so much territory east and west, we have six time zones (not counting the dependencies). Most states (excluding Hawaii, Arizona, and the overseas territories) shift time between Standard Time and Daylight Time.
The acronyms for time zones are capitalized. Depending on how they are used, they may be surrounded by parentheses.
- Hawaii (HST)
- Alaska (AKST, AKDT)
- Pacific (PST, PDT)
- Mountain (MST, MDT)
- Central (CST, CDT)
- Eastern (EST, EDT)
Within a country, one normally only uses the area code, the prefix, and the individual number, the area code being left out within the region.
Within the US, different formats are acceptable:
- 555-111-2222 (preferred by AP and CMoS)
- (555) 111-2222 (accepted as common by CMoS)
- 555 555 2222
Short translations may offer essential information to the reader, but the sentence itself does not need them.
- According to translate.google.com, German uses the same word for both “thank you” and “please” (bitte).
- To travel to Italy, they learned how to say, “Thank you (graze), “Please” (per favore), and “You’re welcome” (prego).
The list may be horizontal (with each item following the previous in the same paragraph) or vertical (each item on its own line).
- Please follow the proper procedure for resetting your clock: (1) press the “time” button, (2) simultaneously press the “hour” button as often as necessary to change the hour, (3) release the “hour” button and continue to hold the “time,” (4) press the “min” button as necessary to change the minutes, (5) release all buttons.
To make ice cream, you need these ingredients:
and a strong arm for turning the churn!
Brackets may be used for clarification within the parentheses or quotation marks. As secondary parentheses. they set off non-essential information.
Translations within a quotation should be enclosed within brackets.
Brackets follow the same rules for ending punctuation and quotation marks as parentheses.
- Every weekend (Saturdays [unless Tommy was playing football] and Sundays), we went to the mountains.
- We had a wonderful time (except for the shark attack [actually, no big deal]) at the beach.
- “Humpy Dumpty [an egg] sat on a wall.”
- “Only two things are infinite [having no end], the universe and human stupidity, and I’m not sure about the former” (Albert Einstein).
- Jacob often said, “Por favor [please]” when he meant, “Gracias [thank you].”
If the error or confusion is located in italicized text, then “[sic]” should be in normal text.
- The handwritten note was sent to all the classrooms, “Students, report too [sic] the auditorium.”
- Benjamin Franklin would have been dismayed if he had seen his saying quoted as “A slip of the foot you may soon recover, but a slip of the tongue you may even [sic] get over.”