Jenny Morse, PhD
Author and CEO

How well do you know colons? Take this pre-quiz to test your knowledge: https://78s4mcvdp5b.typeform.com/to/UWiuXmZF

Let’s make sure we all know what we’re talking about. The colon is the punctuation mark with two dots stacked on top of each other:

That’s right. If you look closely, you’ll see that I used a colon at the end of my sentence to introduce…the colon. And that’s because the colon’s job is to…

Wait, let me ask you first.

What do you use a colon for?

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If you are like most of the professionals I train, you’ll probably give this answer:

Colons are used to introduce lists.

And that’s not wrong, exactly. But it isn’t right either.

Where do you see colons the most? As you are going about your day, where does this mark pop up? Frequently? Often? One might even say–all the time?

Get it? We see colons most frequently in time. For example, as I write this, the clock on my computer shows 6:55pm. The colon is in there, separating the hour and the minute, telling us what hour we are in and then adding more detail about specifically what portion of the hour we are in–the end of the 6 o’clock hour. Nearly the 7 o’clock hour.

Another place where we see colons a lot? Titles, headings, especially movies.

Avengers: Age of Ultron

Pirates of the Caribbean: At World’s End

See, the colon’s purpose isn’t to introduce lists. Not in time. Not in movie headings. The colon’s purpose is to show the relationship between a big idea and its details.

Big idea: Details

That’s why it is often used in lists, because the information before the colon provides some context and the list provides the details.

Groceries:

Milk

Bread

Bananas

So a colon can appear after a heading in order to introduce a list that will give the reader more details following from the heading.

When writing a complete sentence, the colon must follow a complete idea.

Correct I need to get a few things at the store: milk, bread, oj, and bananas.

The colon works here because the information before the colon is a complete sentence. I could just say “I need to get a few things at the store.” You wouldn’t know what the things were, but you wouldn’t think that was an incomplete sentence.

Incorrect I need to get: milk, bread, oj, bananas.

The colon doesn’t work here because “I need to get” is not a complete sentence. I can’t just say to you “I need to get.” That’s a fragment. If I said that to you and stopped at the word “get,” you would look at me funny and expect me to keep talking. If you can’t stop there, you can’t put a colon there.

Correct I need to get milk, bread, oj, and bananas.

This sentence doesn’t need a colon because all the parts contribute to the complete sentence. You can say “I need to get milk.” But “milk” isn’t a detail of the sentence, it’s required for the sentence to make sense. And you can say “I need to get bread,” “I need to get oj,” and “I need to get bananas.” Each item is the object of the verb “get”. You need the objects to make the grammar of the sentence complete.

The most common error with a colon is thinking that it is required before a list. That’s not true. Most lists don’t need a colon at all because the sentence simply continues into the list.

Grammatically, the list is made up of the objects of the verb, and no single punctuation mark can be inserted between the verb and its object.

So, you can’t use a colon after verbs that require objects like “include” or “bring” or any form of the verb “to be”. You also can’t use a colon (or any punctuation) with “like,” “such as,” or any preposition (little words that describe relationships: in, out, over, under, above, beyond, about, to, from, etc. There are like 40 of them.)

If you want to check what you learned, take our post-quiz!

https://78s4mcvdp5b.typeform.com/to/K9pYBPma

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