In the introduction to “Punctuation Toolbox,” I discussed the colon to highlight the necessity of developing a varied and versatile punctuation toolbox.
But what exactly is a colon? (And, no, I don’t mean the colon that helps you digest food!) What does it look like? What is its purpose? This article will answer these questions—and a few others. (And here’s more good news: forty-year-old men don’t have to have these [punctuational] colons examined and cleaned out. Just remember that if you think that punctuation is a pain in the . . . well, you know. . . .)
First things first—here’s what a colon looks like:
: colon (one dot directly over another dot)
But what does a colon do? The easiest way to understand the colon’s function is to think of it as the equal sign of writing. Think about how the equal sign sits between two mathematical expressions that are the same (even if they are written differently). For example, when looking at the mathematical expressions below, consider how what is on one side of the equal sign is actually the same number as what is on the other side—even if the two are written differently. Look:
10 = 10
5 + 5 = 10
10 = 5 + 5
10 = 7 + 3
15 = 3 x 5
2 (5 + 2) = 14
We can even list a bunch of numbers on one side, and sum them up with the “answer” on the other side:
2 + 1 + 3 + 4 = 10
Or we can reverse it, with the sum first and the added parts second:
10 = 2 + 1 + 3 + 4
In other words, “2 + 1 + 3 + 4” is just another way of saying “10.”
“Come on, Chris,” you might be saying, “This isn’t The Mathematician’s Toolbox. Why are you talking about all these numbers?”
I’ll explain. The colon is the equal sign of writing. They even look similar:
: colon (one dot over another dot)
= equal sign (one line over another line)
So how is the colon like the equal sign in terms of function? Consider the sentence below. Notice the parts of the sentence combined by the colon; look at what is to the left of the colon and what is to the right of the colon:
Today I bought ingredients for my (world-famous) broccoli salad: mayonnaise, cheddar cheese, water chestnuts, sliced almonds, red onion, raisins, cheddar cheese, and—last, but not least—broccoli.
In other words, I am saying the same thing on either side of the colon, just in two different ways:
Ingredients for my (world-famous) broccoli salad = mayonnaise, cheddar cheese, water chestnuts, sliced almonds, red onion, raisins, cheddar cheese, and broccoli.
The item to the left of the colon is the sum—the whole item, not broken down into its parts: “ingredients for my (world-famous) broccoli salad.”
The items to the right of the colon simply compose the breakdown of the thing to the right. That list is just an itemized way of saying “ingredients for my (world-famous) broccoli salad.”
In other words, this . . .
Ingredients for my (world-famous) broccoli salad: mayonnaise, cheddar cheese, water chestnuts, sliced almonds, red onion, raisins, cheddar cheese, and broccoli
. . . works just like this . . .
10 = 2 + 1 + 3 + 4
After all, “2 + 2 + 3 + 4” is just a more itemized way of saying “10.”
Do you see it? Like the equal sign, the colon sits between two expressions that state the same concept but in different ways.
The Colon Introduces
Most writing experts will (rightly) say this about the colon: “The colon is an element for introducing the part that follows.” In their brilliant and entertaining punctuation guide, Comma Sense, Richard Lederer and John Shore cleverly call the colon the Ed Sullivan of punctuation, since—like Mr. Sullivan—the colon’s job is to introduce others. That analogy has stayed with me, even as I developed my own ways of teaching colon placement to students.
Here’s how Lederer and Shore put it:
The colon, after all, really doesn’t do much beyond serve as an introducer. And I remember the time on the show when Jack Benny asked Ed what exactly Ed did on the show—and Ed answered with a simple, “I introduce the acts.”
For purposes of this discussion of the colon, I might define the colon this way:
The colon introduces other elements of writing by emphasizing the essential equality of the two items it combines. It introduces by sitting between two different ways of saying the same thing.
So, whether it is introducing a list or simply restating an idea “in other words,” the colon always acts as a type of equal sign between the parts it combines. Take a look at these sample sentences to see how the colon works as both an introducing element and an “equal sign”:
There is only one activity that I enjoy as much as writing: teaching others how to write.
(one activity I enjoy as much as writing = teaching writing to others)
Bob got himself into deep shit yesterday: he was pulled over for speeding—and his license had expired!
(Bob got himself into deep shit yesterday = he was pulled over for speeding—and his license had expired)
I am developing essay-commentary macros with one of my valued colleagues: Professor Michael O’Connor.
(one of my valued colleagues = Professor Michael O’Connor)
Christine enjoys a range of activities: traveling in England, writing about tattoo art, doing complex metal work, and spending time with her son.
(a range of activities = traveling in England, writing about tattoo art, doing complex metal work, and spending time with her son)
The colon can also start with the list to introduce the summary description of the list, like this:
Traveling in England, writing about tattoo art, doing complex metal work, and spending time with her son: these are a few of Christine’s favorite things. (Can’t you just hear John Coltrane playing in the background?)
Do you see how that works? Now you understand the colon: the equal sign of writing.
Next Up: The Semicolon
Well, that’s it for the colon. The next article will discuss the basic use of the semicolon, and from there, other articles will discuss further semicolon details. Want to learn more? Click the link below:
Works Cited
Lederer, Richard and John Shore. Comma Sense: A Fun-damental Guide to Punctuation. New York: St. Martin’s Press, 2005. Print.
Christopher Altman is passionate about bringing the art of effective writing to everyday Americans. In addition to writing this blog, Mr. 
Altman produces and hosts The Writer’s Toolbox Podcast, and he is currently developing a number of book projects that examine the role of language in popular media and everyday life. His book, Myths We Learned in Grade School English, explores how adult writers can overcome the false writing rules learned in childhood. When he is not writing or teaching, Mr. Altman enjoys grilling out and savoring the mild summers of Central New York, where he is a professor of English at Onondaga Community College (Syracuse, NY).
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