It's no accident that a semicolon is a period atop a comma. Like commas, semicolons indicate an audible pause—slightly longer than a comma's, but short of a period's full stop.
Semicolons have other functions, too. But first, a caveat: avoid the common mistake of using a semicolon to replace a colon (see the "Colons" section).
Incorrect: I have one goal; to find her.
Correct: I have one goal: to find her.
Rule 1a. A semicolon can replace a period if the writer wishes to narrow the gap between two closely linked sentences.
Call me tomorrow; you can give me an answer then.
We have paid our dues; we expect all the privileges listed in the contract.
Rule 1b. Avoid a semicolon when a dependent clause comes before an independent clause.
Incorrect: Although they tried; they failed.
Correct: Although they tried, they failed.
Rule 2. Use a semicolon before such words and terms as namely, however, therefore, that is, i.e., for example, e.g., for instance, etc., when they introduce a complete sentence. It is also preferable to use a comma after these words and terms.
Example: Bring any two items; however, sleeping bags and tents are in short supply.
Rule 3. Use a semicolon to separate units of a series when one or more of the units contain commas.
Incorrect: The conference has people who have come from Moscow, Idaho, Springfield, California, Alamo, Tennessee, and other places as well.
Note that with only commas, that sentence is hopeless.
Correct: The conference has people who have come from Moscow, Idaho; Springfield, California; Alamo, Tennessee; and other places as well. (Note the final semicolon, rather than a comma, after Tennessee.)
Rule 4. A semicolon may be used between independent clauses joined by a connector, such as and, but, or, nor, etc., when one or more commas appear in the first clause.
Example: When I finish here, and I will soon, I'll be glad to help you; and that is a promise I will keep.
Rule 5. Do not capitalize ordinary words after a semicolon.
Incorrect: I am here; You are over there.
Correct: I am here; you are over there.
A colon means "that is to say" or "here's what I mean." Colons and semicolons should never be used interchangeably.
Rule 1a. Use a colon to introduce an item or a series of items. Do not capitalize the first item after the colon (unless it's a proper noun).
You know what to do: practice.
You may be required to bring many things: sleeping bags, pans, utensils, and warm clothing.
I want the following items: butter, sugar, and flour.
I need an assistant who can do the following: input data, write reports, and complete tax forms.
Rule 1b. A capital letter generally does not introduce a word, phrase, or incomplete sentence following a colon.
He got what he worked for: a promotion
He got what he worked for: a promotion that paid a higher wage.
Rule 2. Avoid using a colon before a list if it directly follows a verb or preposition that would ordinarily need no punctuation in that sentence.
Not recommended: I want: butter, sugar, and flour.
Recommended: I want butter, sugar, and flour.
Here is what I want: butter, sugar, and flour.
Not recommended: I've seen the greats, including: Barrymore, Guinness, and Streep.
Recommended: I've seen the greats, including Barrymore, Guinness, and Streep.
Rule 3. When listing items one by one, one per line, following a colon, capitalization and ending punctuation are optional when using single words or phrases preceded by letters, numbers, or bullet points. If each point is a complete sentence, capitalize the first word and end the sentence with appropriate ending punctuation. Otherwise, there are no hard and fast rules, except be consistent.
I want an assistant who can do the following:
The following are requested:
These are the pool rules:
Rule 4. A colon instead of a semicolon may be used between independent clauses when the second sentence explains, illustrates, paraphrases, or expands on the first sentence.
Example: He got what he worked for: he really earned that promotion.
If a complete sentence follows a colon, as in the previous example, authorities are divided over whether to capitalize the first word. Some writers and editors feel that capitalizing a complete sentence after a colon is always advisable. Others advise against it. Still others regard it as a judgment call: If what follows the colon is closely related to what precedes it, there is no need for a capital. But if what follows is a general or formal statement, many writers and editors capitalize the first word.
Example: Remember the old saying: Be careful what you wish for.
Rule 5. Capitalize the first word of a complete or full-sentence quotation that follows a colon.
Example: The host made an announcement: "You are all staying for dinner."
Rule 6. Capitalize the first word after a colon if the information following the colon requires two or more complete sentences.
Example: Dad gave us these rules to live by: Work hard. Be honest. Always show up on time.
Rule 7. If a quotation contains two or more sentences, many writers and editors introduce it with a colon rather than a comma.
Example: Dad often said to me: "Work hard. Be honest. Always show up on time."
Rule 8. For extended quotations introduced by a colon, some style manuals say to indent one-half inch on both the left and right margins; others say to indent only on the left margin. Quotation marks are not used.
Example: The author of Touched, Jane Straus, wrote in the first chapter:
Georgia went back to her bed and stared at the intricate patterns of burned moth wings in the translucent glass of the overhead light. Her father was in "hyper mode" again where nothing could calm him down.
Rule 9. Use a colon rather than a comma to follow the salutation in a business letter, even when addressing someone by his or her first name. (Never use a semicolon after a salutation.) A comma is used after the salutation in more informal correspondence.
Dear Ms. Rodriguez:
The rules set forth in this section are customary in the United States. Great Britain and other countries in the Commonwealth of Nations are governed by quite different conventions. Nowhere is this more apparent than in Rule 4 in this section, a rule that has the advantage of being far simpler than Britain's and the disadvantage of being far less logical.
Rule 1. Use double quotation marks to set off a direct (word-for-word) quotation.
Correct: "I hope you will be here," he said.
Incorrect: He said that he "hoped I would be there." (The quotation marks are incorrect because hoped I would be there does not state the speaker's exact words.)
Rule 2a. Always capitalize the first word in a complete quotation, even midsentence.
Example: Lamarr said, "The case is far from over, and we will win."
Rule 2b. Do not capitalize quoted material that continues a sentence.
Example: Lamarr said that the case was "far from over" and that "we will win."
Rule 3a. Use commas to introduce or interrupt direct quotations.
He said, "I don't care."
"Why," I asked, "don't you care?"
This rule is optional with one-word quotations.
Example: He said "Stop."
Rule 3b. If the quotation comes before he said, she wrote, they reported, Dana insisted, or a similar attribution, end the quoted material with a comma, even if it is only one word.
"I don't care," he said.
"Stop," he said.
Rule 3c. If a quotation functions as a subject or object in a sentence, it might not need a comma.
Is "I don't care" all you can say to me?
Saying "Stop the car" was a mistake.
Rule 4. Periods and commas ALWAYS go inside quotation marks.
The sign said, "Walk." Then it said, "Don't Walk," then, "Walk," all within thirty seconds.
He yelled, "Hurry up."
Rule 5a. The placement of question marks with quotation marks follows logic. If a question is within the quoted material, a question mark should be placed inside the quotation marks.
She asked, "Will you still be my friend?"
The question Will you still be my friend? is part of the quotation.
Do you agree with the saying, "All's fair in love and war"?
The question Do you agree with the saying? is outside the quotation.
Rule 5b. If a quoted question ends in midsentence, the question mark replaces a comma.
Example: "Will you still be my friend?" she asked.
Rule 6. Quotation marks are used for components, such as chapter titles in a book, individual episodes of a TV series, songs from a Broadway show or a music album, titles of articles or essays in print or online, and shorter works such as short stories and poems.
It is customary in American publishing to put the title of an entire composition in italics. Put the title of a short work—one that is or could be part of a larger undertaking—in quotation marks.
A "composition" is a creative, journalistic, or scholarly enterprise that is whole, complex, a thing unto itself. This includes books, movies, plays, TV shows, newspapers, magazines, websites, music albums, operas, musical theater, paintings, sculptures, and other works of art.
Example: Richard Burton performed the song "Camelot" in the 1960 Broadway musical Camelot.
Although the word is the same, "Camelot" the song takes quotation marks because it's part of a larger work—namely, a full-length show called Camelot.
Rule 7. Use single quotation marks for quotations within quotations.
Example: Dan said: "In a town outside Brisbane, I saw 'Tourists go home' written on a wall. But then someone told me, 'Pay it no mind, lad.' "
Note that the period goes inside both the single and double quotation marks. Also note that, as a courtesy, there is visible space between adjacent single and double quotation marks.
Rule 8a. Quotation marks are often used with technical terms, terms used in an unusual way, or other expressions that vary from standard usage.
It's an oil-extraction method known as "fracking."
He did some "experimenting" in his college days.
I had a visit from my "friend" the tax man.
Rule 8b. Never use single quotation marks in sentences like the previous three.
Incorrect: I had a visit from my 'friend' the tax man.
The single quotation marks in the above sentence are intended to send a message to the reader that friend is being used in a special way: in this case, sarcastically. Avoid this invalid usage. Single quotation marks are valid only within a quotation, as per Rule 7, above.
Rule 9. When quoted material runs more than one paragraph, start each new paragraph with opening quotation marks, but do not use closing quotation marks until the end of the passage.
She wrote: "I don't paint anymore. For a while I thought it was just a phase that I'd get over.
"Now, I don't even try."