Proper Use of The Colon

By Mark Nichol

The colon is a versatile punctuation mark. Here are its three primary functions, followed by a few other uses:

Definition or Expansion

“But here’s the interesting thing: He hadn’t ever been there before.”

Note the capitalization of the first word after the colon. All usage guides agree that in a sentence like “I want you to tell me one thing: the truth,” the first word should be lowercase because it begins a phrase, not a complete sentence. But handbooks are divided over whether to capitalize complete sentences.

The Chicago Manual of Style advises doing so only when the defining or expanding passage following the colon consists of two or more sentences. Others disagree, and though I usually follow Chicago, I concur with them: It can be difficult in a passage to know when the definition or expansion ends, and the distinction between a single sentence and two or more seems trivial and inconsistent.

Setting up a Quotation

He makes this moral argument: “Taking whatever we need from the world to support our comfortable lives is not worthy of us as moral beings.”

Note that the colon concludes an independent clause that introduces a statement; it brings the reader to a temporary halt. Writers, ignoring the grammatical distinction between this construction and a simple attribution, widely but incorrectly use colons in place of commas, as in this erroneous usage: “He voted against it, declaring: ‘The only thing this bill will stimulate is the national debt.’” In this case, or after “He said” or “She asked” or a similar term, a simple comma suffices.

Introducing a List

When a phrase that introduces a numbered, unnumbered, or bullet list, or a run-in list, syntactically comes to a stop, use the colon as the bumper:

“The two central questions in ethical theories are as follows:
1. What is the good for which we strive or should strive, and what is the evil that we would like to or must avoid?
2. What is the proper or desired course of action, and what is the inappropriate or forbidden course of action?”

But when each item in the list is an incomplete sentence that continues an introductory phrase, omit it:

“For this experiment, you will need electrical wire (at least 3 feet), a pair of wire cutters, a battery, a flashlight bulb, and electrical tape.”

When, in the latter example, the list is formatted with the introductory phrase and each item on its own line, “For this experiment, you will need” remains bereft of a colon, and each item ends with a period.

(Notice that my explanatory introduction to each list type above is closed, with a colon.)

Colons are used in several other ways to clarify relationships between words and numbers: They set off a character’s name from a line of dialogue in a script; separate titles and subtitles of books, films, and other works; distinguish between chapter and verse in reference to books of the Bible and in similar usages; and separate numerals denoting hours, minutes, and other units of time.

In addition, they have specific functions in mathematics, logic, and computer programming, as well as informal roles in setting actions or sounds apart from words in email and online chats (much as parentheses are used in quotations and dialogue) and as a basic character in emoticons (arrangements of punctuation marks and other symbols to simulate a facial expression).

But it is when the colon is employed in one of the three primary purposes that errors are most likely to appear and communication is most likely to be compromised.

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20 Responses to “Proper Use of The Colon”

  • Tony

    “Others disagree, and though I usually follow Chicago, I concur with them: It can be difficult in a passage to know when the definition or expansion ends, and the distinction between a single sentence and two or more seems trivial and inconsistent.”

    I am confused: You say you concur, but it appears you do not. I am also confused about your use of the coma in the first part: My thought it that the coma belongs between the words ‘and’ and ‘though’. Of course, I’m having a lot of fun overusing the colon here.

    Thanks!
    -Tony

  • Roger

    Thanks for this. I have been very interested/confused about the first point you make (whether to capitalise the first word after the colon) and what you’ve noted here is very helpful.

  • briantw

    Ambiguous sentence: “Others disagree, and though I usually follow Chicago, I concur with them:”

    At first, I thought you were using ‘concur’ incorrectly, until I figured out that it is not Chicago with whom you concur.

  • Rebecca

    Thanks for the reminder! The use of the colon does get confusing.

  • Amber Polo

    Would you encourage the use of colons in fiction? Sometimes they seem out of place.

  • Tony

    Hello,

    I left a comment early this morning (1:42 am) and I see it is still awaiting moderation, though two comments submitted later have been approved. I was not trying to be critical. In fact, I subscribe to the dailywritingtips.com RSS feed and appreciate the work that goes into each and every article.

    I am genuinely confused about the questions I posed and would appreciate a response. My comment about my “overusing the colon” was a double entendre, the negative connotation aimed at myself 🙂

    So, I did not mean to offend.

  • Cheerful Charlie

    Thanks! Now could you please explain the use of the comma in the following sentence:

    (Notice that my explanatory introduction to each list type above is closed, with a colon.)

  • Dan

    This is a great topic to bring up. I often use a column and introduce a list of things in the following way. Can you comment on the grammatical accuracy and phrasing of it?

    ——————————————–

    Hi XYZ,

    I have a few issues with the spreadsheet that you sent me, they are as follows:

    1.
    2.
    3.

    —————————-

  • Precise Edit

    The colon serves as the end punctuation to an independent clause, which means the text before a colon must be a complete sentence.

    One mistake (which you also point out) is using a colon to introduce a series. For example, this example is incorrect.
    “I need to buy: grapes, peaches, and tomatoes.”

    Here, “I need to buy” is not an independent clause. It cannot serve as a complete sentence, so it should not be followed by a colon. The correct punctuation for this series is a follows.
    “I need to buy grapes, peaches, and tomatoes.”

    To use the colon in this example, we can revise the sentence in this way: “I need to buy three things: grapes, peaches, and tomatoes.” This is the correct use of the colon because “I need to buy three things” is an independent clause.

    @Dan
    The colon is correct, but the comma is not.
    The expression “they are as follows” is an independent clause, so you can follow it with a colon.

    However, you have a comma splice. You joined the first two independent clauses with only a comma. Instead, you can use comma-“and,” a semicolon, or a period. Here is one correct option for you:
    “I have a few issues with the spreadsheet that you sent me. They are as follows: . . . .

  • Mark Nichol

    Tony and briantw:

    Yes, “Others disagree, and though I usually follow Chicago, I concur with them” is ambiguous. I concur with the others, not with Chicago.

    Tony, no offense taken. The order in which comments appear has nothing to do with comment content and does not represent a popularity contest.

    Also, “Others disagree, and though I usually follow Chicago, I concur with them” could also be punctuated as follows: “Others disagree and, though I usually follow Chicago, I concur with them,” as well as “Others disagree, and, though I usually follow Chicago, I concur with them.”

    The latter two forms indicate that “though I usually follow Chicago” is a parenthetical phrase inserted into “Others agree(,) and I concur with them.” But it’s also correct to combine two independent clauses: “others disagree,” and “(and) though I usually . . . .”

  • Mark Nichol

    Cheerful:

    The comma conveys a subtle difference in emphasis:

    In “Notice that my explanatory introduction to each list type above is closed with a colon,” the emphasis is on colon. But I didn’t want to imply that my point is that I used a colon, rather than another punctuation mark.

    In “Notice that my explanatory introduction to each list type above is closed, with a colon,” I emphasize closed, with an appended explanatory phrase. In this way, I called attention to the fact that the phrases are closed rather than what they are closed with.

  • Liz D

    The Associated Press Stylebook says the following regarding the colon, “The most frequent use of a colon is at the end of a sentence to introduce lists, tabulations, etc. Capitalize the first word after a colon only if it is a proper noun or the start of a complete sentence…”

  • Lynn

    I was taught that a colon should never follow a preposition or a verb. Therefore, using it after the expression “as follows” is incorrect. (I consulted dear Uncle Warner.)

  • Ron

    I used a colon in the following sentence, and while I realize that the colon should follow a complete sentence, I also know that English rules can be broken simply when ‘it works better.’

    Again and again and again: You don’t read very well, do you?

  • Mick

    I was corrected on the following use of colons without a reason or even a rule and wondered what that reason might be.

    Let the three vertices be labeled A: (5,6), B: (7,-2), and C: (-5, 7).

  • Mark Nichol

    Lynn:

    Good point, but the idea is that the colon should never follow one part of speech or the other in the midst of a sentence. “As follows,” however, brings the clause to a close, and the colon brings it to a grinding halt, signaling that an elucidation follows.

  • Mark Nichol

    Mick:

    I disagree with the rule you were given without explanation; because, in the example you provided, the colons are redundant to the parentheses in calling attention to the pairs of values, there’s no use for them :

    “Let the three vertices be labeled A (5,6), B (7,-2), and C (-5, 7).”

  • S

    “Others disagree, and though I usually follow Chicago, I concur with them: It can be difficult in a passage to know when the definition or expansion ends, and the distinction between a single sentence and two or more seems trivial and inconsistent.”

    First of all, regarding the above quote from your article, good point, Mr. Nichol. While I am a devotee of Chicago style, I’m glad I’m not the only one who feels that some of Chicago’s guidelines for capitalization after colons in running text are a tad head-scratch inducing.

    I was surprised to see that some of the people who commented on this post found the quoted segment from the original article so confusing.

    From a strictly grammatical point of view, there is no ambiguity of meaning. “Others” is a plural term. “Chicago” (style) is singular. So when the author concurs with “them,” he’s expressing agreement between the two plural terms.

    Erp. Perhaps I’m just too much of a grammar robot.

    Anyway, thanks for pointing out–in plain English–the correct usage of the colon, Mr. Nichol. Your article makes valid points in an easily comprehensible fashion. Bravo.

  • Roni

    Lately, I have seen the colon used in novels as it is used in plays.
    Instead of writing:

    Sara said, “Blah blah.” I am seeing Sara:Blah, blah.

    Is this correct and why is it being used? Perhaps to eliminate the repitition of the word said when creating dialog? Thank you.

  • Roni

    I meant to write,
    Sara:”Blah, blah.” Sorry.

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