Colons (and How They Differ from Semicolons)

Recently I came across two expressions sorely in need of a well-placed colon. The first appeared in the Washington Post*:

Although the vaccines remain remarkably effective, the virus has bountiful opportunities to find new ways to evade immunity. Most of the world remains unvaccinated.

Had the writer used a colon after the first sentence, the reader would have known immediately that “the virus has bountiful opportunities to evade immunity” precisely because “most of the world remains unvaccinated.” But without the colon, the reader must make that logical—and critical—connection. Next I stumbled across the words to a favorite song, “The Riddle” by Five for Fighting. Written in verse form, the lyrics—as is often the case with poetry—contain no punctuation at all (at least not in versions found online).

Of course, song lyrics—like other poems—often take poetic license with punctuation. But with all due respect to singer-songwriter John Ondrasik, a well-placed colon would enhance the refrain in this fine song: “There’s a reason for the world: you and I.”

In clarifying that the phrase “you and I” is an appositive for the word reason, the colon underscores the central idea of the song: you and I are the reason for the world.

In both of these examples, the reader will likely figure out the intended meaning, but as writers, it is our job to make the meaning as clear as possible for the reader—and to do so as quickly as possible. The colon can help us do both.

Far too many writers ignore the colon altogether, unsure of how it works. Others confuse the colon with the semicolon or insert it in places where it doesn’t grammatically belong. And writers are sometimes confused about whether to capitalize a sentence following a colon.

This article was written to give you the confidence you need to add the colon to your writer’s toolbox.

How Much Do You Already Know?

Let’s start by finding out what you already know. Can you spot errors in the use of the colon in any of the following sentences?

1. Return the item in its original package to: 221 Barnwell Street, Columbus, GA 12345.
2. The conference speakers who were chosen by the steering committee included: Sean Baldwin, Tiffany Chen, and Juan Vanelli.
3. The three most important assets a hotel manager can have are: patience, charm, and intelligence.
4. Applications should be submitted to this address: Post Office Box 322, Hartwell, FL 98204.
5. The following employees have won awards for their proposals: Mark Jordan, Cynthia Meyers, and Deborah Hollowell.

The first three sentences misuse the colon, while the last two are correct.

The Colon vs. the Semicolon

In a post and in a video on the use of the semicolon, I explain that we use that mark of punctuation most commonly between two independent clauses. An independent clause is a group of words that can stand alone as a sentence. That is, it expresses a thought that is both grammatically and logically complete. (In this video I explain how to recognize an independent clause.) The key difference between the colon and the semicolon is that colons do not have to have an independent clause after them. Colons are quite often followed by lists comprising single words or noun phrases, as is the case with sentence five above, with its list of names.

Sentences 1, 2, and 3 misuse the colon, then, because in each case the colon follows a group of words that is logically incomplete. (Of course, semicolons can also be used between items in a list when one or more of those items includes a comma—read more here.)

Colons Follow Complete Thoughts (Independent Clauses)

One way to test whether the colon is grammatically appropriate is to ask if the group of words before the colon could grammatically end with a period:

• Send check or money order to.
• The conference speakers who were chosen by the steering committee included.
• The three most important assets a hotel manager can have are.

We can see clearly in each of these examples that critical information is missing and that these are not independent clauses. We need neither a period nor a colon in such constructions:

• Send check or money order to 221 Barnwell Street, Columbus, GA 12345.
• The conference speakers who were chosen by the steering committee included Sean Baldwin, Tiffany Chen, and Juan Vanelli.
• The three most important assets a hotel manager can have are patience, charm, and intelligence.

Sentences 4 and 5 correctly use the colon because the information before the colon in each case is logically complete; that is, it is an independent clause, capable of standing alone as a sentence.

Say It Out Loud

Notice that when we say these sentences aloud, we can hear our voices drop when we get to the colons just as our voices drop at the end of sentences:

• Applications should be submitted to the following address.
• The following employees have won awards for their proposals.

What Follows a Colon Does Not Have to Be Independent

While we must have an independent clause on both sides of the semicolon, the colon may be followed by a single word or any group of words providing the information hinted at in the logically complete independent clause preceding it. Sentences 4 and 5 provide us with good examples of colons followed by phrases. Sentence 4 is followed by an address, which is a phrase and certainly not an independent clause:

• Applications should be submitted to the following address: Post Office Box 322, Hartwell, FL 98204.

In sentence 5, the colon is followed by a list, which is also a phrase:

• The following employees have won awards for their proposals: Mark Jordan, Cynthia Meyers, and Deborah Hollowell.

Notice that while the independent clause in each of these sentences is complete grammatically (that is, we could put a period after the words address and proposals), it still leaves us without details: what is the address, and who are the award recipients? The colon is appropriate because the list in each case gives us the information that the independent clause withholds.

Colon or Semicolon between Two Independent Clauses?

The situation gets a bit more complicated when we have two independent clauses and have to decide which mark of punctuation, the colon or the semicolon, is more appropriate. Consider these two sentences:

• John has a serious problem; he is seeking professional help.
• John has a serious problem: he does not know how to relax.

Both sentences contain two complete thoughts—two independent clauses—but the relationship between the two clauses in each case is quite different. In the first sentence, the second clause merely adds to the thought expressed in the first clause. However, it does not answer the question hinted at in the first clause; we are still left to wonder about the nature of John’s problem. In the second sentence, the relationship between the two independent clauses is different: the second clause provides the information hinted at in the first. That is, it reveals the nature of John’s problem.

Using the Colon Before Some Direct Quotations

Another time when the colon comes in handy is before certain direct quotations. If a quotation is introduced by an independent clause—especially if the quotation is, itself, an independent clause—we use a colon instead of a comma or a period. Notice that in this example both the quotation and the information introducing it are independent clauses:

• The chairman was forceful in his pleas for help: “Employees must do their part to make this company profitable in the third quarter.”

Even when the quotation is not an independent clause, if a sentence precedes the quotation, then the colon is a better choice than a comma. Consider this example:

• The sign at the campsite left no room for ambiguity: “Absolutely no littering!”

The Chicago Manual of Style—my style manual of choice—adds that the colon is often used before quotations longer than one complete sentence, even when the introductory text is not an independent clause. Here is an example:

• As Aristotle asserted: “We are what we repeatedly do. Excellence, then, is not an act but a habit.”

Capitalization after the Colon

With a few exceptions, most style books agree that if only a single independent clause follows a colon, we should not capitalize the first letter. Of course, as is often the case, exceptions do exist: we capitalize absolutely in “The sign at the campsite left no room for ambiguity: “Absolutely no littering!” because it is capitalized on the original sign. Also, if the colon is followed by a complete sentence that is also a quotation, we would capitalize the first word. And if more than one sentence follows a colon, we should start each with a capital letter.

Colons in Other Situations

Remember that just because a list is vertical (numbered or bulleted) does not mean it needs a colon to introduce it; we still need an independent clause before the colon. I explore this topic in detail in the article on this site titled “Vertical Lists.” And of course, we sometimes use colons after phrases that serve as headings, but here we are talking about the proper use of the colon in sentences.

TEST YOURSELF

Add or delete colons where appropriate in the following sentences:

1. We have a word for the European interpretation of Asian motifs in a decorative capacity, chinoiserie.
2. Three projects will be completed during the next fiscal year the Smith Mountain Tunnel, the Marsh Springs Bridge, and the Simpson Island Connector.
3. During the next fiscal year, we will complete the Smith Mountain Tunnel, the Marsh Springs Bridge, and the Simpson Island Connector.
4. We were asked to send our letters of recommendation to 234 Miller Lane, Greenville, MO 29292.
5. Everyone in the audience was appalled at the candidate’s bluntness when he said: “My opponent is a crook.”

ANSWERS

1. We have a word for the European interpretation of Asian motifs in a decorative capacity: chinoiserie. [Note that the comma isn’t wrong, but the colon is the better choice behind the independent clause.]
2. Three projects will be completed during the next fiscal year: the Smith Mountain Tunnel, the Marsh Springs Bridge, and the Simpson Island Connector.
3. correct
4. correct
5. Everyone in the audience was appalled at the candidate’s bluntness when he said, “My opponent is a crook.” OR Everyone in the audience was appalled at the candidate’s bluntness: “My opponent is a crook.”

*The irony is not lost on me that the title of the Washington Post article from which I took the quote at the top of this post is misused, according to the guidelines here. Keep in mind, though that the Associated Press style guide, which governs journalism, is an outlier on a number of issues, including the use of the colon. See the article about style guides elsewhere on this site for more details. One has to be a subscriber to read the article, but here is the citation: “In this summer of covid freedom, disease experts warn: ‘The world needs a reality check.’” (17 July 2021)

©2002 Get It Write. Revised 2021.