The colon is a widely misused but very useful piece of punctuation. Use it correctly and it can add precision to your written work as well as impressing your tutors and future employers. There are not many people around who are able to use colons correctly. The colon has a number of functions:
To introduce an idea.
The colon has two main uses. Firstly it is used to introduce an idea that is an explanation or continuation of the one that comes before the colon. The colon can be considered as a gateway inviting the reader to go on. Have a look at these examples:
You are left with only one option: Press on until you have mastered it.
There is one thing you need to know about coleslaw: it looks and tastes like slurry.
In the above examples you have some idea of what will come after the colon. It is important to note that the clause that comes before the colon can stand alone and make complete sense on its own.
If the initial clause cannot stand alone and make complete sense, you should not use a colon.
There is some debate about whether the clause following the colon should begin with a capital letter or not. If the colon precedes a formal quote, you should begin the language of that quote with a capital letter. If the explanation that follows the colon contains more than one sentence, you should use a capital letter. In other cases, some guides simply advise consistency, others advise that a capital should always be used.
To introduce a list.
The second main use of the colon is to introduce a list. You need to take care; many people assume that a colon always precedes a list. This is not the case. Again it is important to remember that the clause that precedes the colon must make complete sense on its own.
Have a look at these examples:
The potion contained some exotic ingredients: snails' eyes, bats' tongues and garlic.
The magic potion contained sesame seeds, bran flakes and coleslaw.
In the first sentence, the clause preceding the colon has a subject and a predicate and makes complete sense on its own 'The potion contained some exotic ingredients.' In the second sentence a colon should not be used, as the clause that would precede it would not make sense alone 'The magic potion contained'.
To introduce quoted material.
The colon has other uses: it can also be used after a clause introducing quoted material. Have a look at this example.
The director often used her favourite quotation from Monty Python: 'I wasn't expecting the Spanish Inquisition.'
If the colon precedes a quotation, you should begin the language of that quote with a capital letter.Have a go at this question.
Which of these sentences uses the colon correctly.
Having mastered the correct use of the colon, it is useful to make it work for you in your writing. Using a colon can add emphasis to an idea. For example, consider the following two sentences:
The one thing mankind cannot live without is hope.
There is one thing that mankind cannot live without: hope.
Both sentences are grammatically correct, but the second makes the point a little more forcefully. Now we are in the realms of style, it is important to emphasise that you, as the writer, have to decide how to make your newfound expertise with punctuation work for you. Do not be tempted to overuse colons. They are powerful but should be used with precision and care.
Practise using the colon to improve your writing style with this exercise.
Test your understanding with these exercises.