Semi-colons, colons, and dashes

What this handout is about

This handout explains the most common uses of three kinds of punctuation: semi-colons (;), colons (:), and dashes (—). After reading the handout, you will be better able to decide when to use these forms of punctuation in your own writing.

Semi-colons

The semi-colon looks like a comma with a period above it, and this can be a good way to remember what it does. A semi-colon creates more separation between thoughts than a comma does but less than a period does. Here are the two most common uses of the semi-colon:

To help separate items in a list, when some of those items already contain commas. Let’s look at an example, as that is the easiest way to understand this use of the semi-colon. Suppose I want to list three items that I bought at the grocery store:

  • apples
  • grapes
  • pears

In a sentence, I would separate these items with commas:

  • I bought apples, grapes, and pears.

Now suppose that the three items I want to list are described in phrases that already contain some commas:

  • shiny, ripe apples
  • small, sweet, juicy grapes
  • firm pears

If I use commas to separate these items, my sentence looks like this:

  • I bought shiny, ripe apples, small, sweet, juicy grapes, and firm pears.

That middle part is a bit confusing—it doesn’t give the reader many visual cues about how many items are in the list, or about which words should be grouped together. Here is where the semi-colon can help. The commas between items can be “bumped up” a notch and turned into semi-colons, so that readers can easily tell how many items are in the list and which words go together:

  • I bought shiny, ripe apples; small, sweet, juicy grapes; and firm pears.

To join two sentences. An independent clause is a group of words that can stand on its own (independently)—it is a complete sentence. Semi-colons can be used between two independent clauses. The semi-colon keeps the clauses somewhat separate, like a period would do, so we can easily tell which ideas belong to which clause. But it also suggests that there may be a close relationship between the two clauses—closer than you would expect if there were a period between them. Let’s look at a few examples. Here are a few fine independent clauses, standing on their own as complete sentences:

  • I went to the grocery store today. I bought a ton of fruit. Apples, grapes, and pears were on sale.

Now—where could semi-colons fit in here? They could be used to join two (but not all three) of the independent clauses together. So either of these pairs of sentences would be o.k.:

  • I went to the grocery store today; I bought a ton of fruit. Apples, grapes, and pears were all on sale.

OR

  • I went to the grocery store today. I bought a ton of fruit; apples, grapes, and pears were all on sale.

I could NOT do this:

  • I went to the grocery store today; I bought a ton of fruit; apples, grapes, and pears were all on sale.

But why I would want to use a semi-colon here, anyway? One reason might have to do with style: the three short sentences sound kind of choppy or abrupt. A stronger reason might be if I wanted to emphasize a relationship between two of the sentences. If I connect “I bought a ton of fruit” and “Apples, grapes, and pears were all on sale” more closely, readers may realize that the reason why I bought so much fruit is that there was a great sale on it.

Colons

Colons follow independent clauses (clauses that could stand alone as sentences) and can be used to present an explanation, draw attention to something, or join ideas together.

Common uses of colons

To announce, introduce, or direct attention to a list, a noun or noun phrase, a quotation, or an example/explanation. You can use a colon to draw attention to many things in your writing. The categories listed below often overlap, so don’t worry too much about whether your intended use of the colon fits one category perfectly.

  • Lists/series example: We covered many of the fundamentals in our writing class: grammar, punctuation, style, and voice.
  • Noun/noun phrase example: My roommate gave me the things I needed most: companionship and quiet.
  • Quotation example: Shakespeare said it best: “To thine own self be true.”
  • Example/explanation example: Many graduate students discover that there is a dark side to academia: late nights, high stress, and a crippling addiction to caffeinated beverages.

To join sentences. You can use a colon to connect two sentences when the second sentence summarizes, sharpens, or explains the first. Both sentences should be complete, and their content should be very closely related. Note that if you use colons this way too often, it can break up the flow of your writing. So don’t go colon-crazy!

  • Example: Life is like a puzzle: half the fun is in trying to work it out.

To express time, in titles, and as part of other writing conventions. Colons appear in several standard or conventional places in writing. Here are a few examples:

  • With numbers. Colons are used to separate units of time (4:45:00 expresses four hours, forty-five minutes, and zero seconds); ratios (2:1), and Bible verses and chapters (Matthew 2:24).
  • In bibliography entries. Many citation styles use a colon to separate information in bibliography entries.
    • Example: Kurlansky, M. (2002). Salt: A world history. New York, NY: Walker and Co.
  • With subtitles. Colons are used to separate titles from subtitles.
    • Example: Everest: The Last Frontier
  • After the salutation in a formal business letter. A colon can be used immediately after the greeting in a formal letter (less-formal letters tend to use a comma in this location).
    • Example:
      To Whom it May Concern:
      Please accept my application for the position advertised in the News and Observer.

Common colon mistakes

Using a colon between a verb and its object or complement

  • Example (incorrect): The very best peaches are: those that are grown in the great state of Georgia.

To correct this, simply remove the colon.

Using a colon between a preposition and its object

  • Example (incorrect): My favorite cake is made of: carrots, flour, butter, eggs, and cream cheese icing.

To correct this, simply remove the colon.

Using a colon after “such as,” “including,” “especially,” and similar phrases. This violates the rule that the material preceding the colon must be a complete thought. Look, for example, at the following sentence:

  • Example (incorrect): There are many different types of paper, including: college ruled, wide ruled, and plain copy paper.

You can see that “There are many different types of paper, including” is not a complete sentence. The colon should simply be removed.

How to check for mistakes

Ask yourself a question: does the material preceding the colon stand on its own? One way to tell if the colon has been properly used is to look only at the words that come in front of the colon. Do they make a complete thought? If not, you may be using the colon improperly. Check above to see if you have made one of the most common mistakes.

Should you capitalize the first letter after a colon?

The first word following the colon should be lower-cased if the words after the colon form a dependent clause (that is, if they could not stand on their own as a complete sentence). If the following phrase is a complete (independent) clause, you may choose to capitalize it or not. Whichever approach you choose, be sure to be consistent throughout your paper.

        Example with an independent clause, showing two different approaches to capitalization:

        • The commercials had one message: The geeks shall inherit the earth. (correct)
        • The commercials had one message: the geeks shall inherit the earth. (correct)

Example with a dependent clause (which is not capitalized)

      • There are three things that I love more than anything else in the world: my family, my friends, and my computer. (correct)

Dashes

The first thing to know when talking about dashes is that they are almost never required by the laws of grammar and punctuation. Overusing dashes can break up the flow of your writing, making it choppy or even difficult to follow, so don’t overdo it.

It’s also important to distinguish between dashes and hyphens. Hyphens are shorter lines (-); they are most often used to show connections between words that are working as a unit (for example, you might see adjectives like “well-intentioned”) or to spell certain words (like “e-mail”).

With that background information in mind, let’s take a look at some ways to put dashes to work in your writing.

To set off material for emphasis. Think of dashes as the opposite of parentheses. Where parentheses indicate that the reader should put less emphasis on the enclosed material, dashes indicate that the reader should pay more attention to the material between the dashes. Dashes add drama—parentheses whisper. Dashes can be used for emphasis in several ways:

        A single dash can emphasize material at the beginning or end of a sentence.

        • Example: After eighty years of dreaming, the elderly man realized it was time to finally revisit the land of his youth—Ireland.
        • Example: “The Office”—a harmless television program or a dangerously subversive guide to delinquency in the workplace?

Two dashes can emphasize material in the middle of a sentence. Some style and grammar guides even permit you to write a complete sentence within the dashes.

        • Example: Everything I saw in my new neighborhood—from the graceful elm trees to the stately brick buildings—reminded me of my alma mater.
        • Example (complete sentence): The students—they were each over the age of eighteen—lined up in the streets to vote for the presidential candidates.

Two dashes can emphasize a modifier. Words or phrases that describe a noun can be set off with dashes if you wish to emphasize them.

      • Example: The fairgrounds—cold and wet in the October rain—were deserted.
      • Example: Nettie—her chin held high—walked out into the storm.

To indicate sentence introductions or conclusions. You can sometimes use a dash to help readers see that certain words are meant as an introduction or conclusion to your sentence.

  • Example: Books, paper, pencils—many students lacked even the simplest tools for learning in nineteenth-century America.
  • Example: To improve their health, Americans should critically examine the foods that they eat—fast food, fatty fried foods, junk food, and sugary snacks.

To mark “bonus phrases.” Phrases that add information or clarify but are not necessary to the meaning of a sentence are ordinarily set off with commas. But when the phrase itself already contains one or more commas, dashes can help readers understand the sentence.

  • Slightly confusing example with commas: Even the simplest tasks, washing, dressing, and going to work, were nearly impossible after I broke my leg.
  • Better example with dashes: Even the simplest tasks—washing, dressing, and going to work—were nearly impossible after I broke my leg.

To break up dialogue. In written dialogue, if a speaker suddenly or abruptly stops speaking, hesitates in speech, or is cut off by another speaker, a dash can indicate the pause or interruption.

  • Example: “I—I don’t know what you’re talking about,” denied the politician.
  • Example: Mimi began to explain herself, saying, “I was thinking—”
    “I don’t care what you were thinking,” Rodolpho interrupted.

We hope that this handout has helped you better understand colons, semi-colons, and dashes! For more information about punctuation, be sure to check out our handout on commas.


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