The Colon and How to Use It

The colon is a useful punctuation mark, but it should only be used in certain circumstances. In this post, we’ll look at how the colon should be used in academic writing.

Explanations, Definitions and Descriptions

One of the most common uses of a colon is to introduce an explanation, definition or description related to the preceding clause. For example, we might say:

I have strong feelings about music: I love heavy metal, but I hate country and western!

Here, the information after the colon is an explanation of the statement that comes before. Generally, the clause after the colon should be more specific than the one preceding it.

While the clause before a colon should be a full sentence, the information that comes after can be as little as one word:

There’s only one thing I need on my toast: Vegemite.

This makes colons different from semicolons, which should only be used to connect full sentences.

Colons and Lists

Another common use of a colon is to introduce a list of items, such as in:

The following ingredients are needed to make pancakes: flour, eggs and milk.

However, no colon is required if the list follows directly from the preceding sentence. As such, the following would be incorrect:

The ingredients needed to make pancakes are: flour, eggs and milk.

This is because the use of ‘are’ would make the sentence complete without the colon.

As with using a colon to introduce an explanation, the clause preceding the list should be a full sentence.

Other Uses of the Colon

In an essay, the other main use for colons is to introduce long, indented quotations (generally over two lines long) on the next line from the main text. For instance:

According to the Nietzsche (1984, p. 126) aphorism from Beyond Good and Evil:

Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you.

How we should understand this is open to interpretation…

It’s also common to use a colon to separate a main title from a subtitle, such as in the full name of the book quoted above (Beyond Good and Evil: Prelude to a Philosophy of the Future).

Colons can also be used in several other situations, including:

Writing ratios (e.g. ‘2:3’)

Introducing speech in a play (e.g. ‘Macbeth: Is this a dagger which I see before me?’)

Introducing an example (as you might have noticed in this blogpost!)

If you can remember all of these, you should be able to use colons correctly in your work.