Colons for Introductions

The Quick Answer
A colon can be used after an introduction. For example:
  • I like the following pies: cheese and onion, chicken and mushroom, and beef and ale.
For a list in normal text (like the one above), the introduction before the colon should be a clause which can stand alone.

When an introduction and a colon introduce a vertical list (e.g., bulleted list), there is far more leniency. In other words, the introduction can be a short introduction which does not stand alone. For example:
  • Select from:
    • cheese and onion
    • chicken and mushroom
    • beef and ale.              
When writing normally (i.e., not a vertical list), do not use a colon after an incomplete introduction. For example:
  • Select from: cheese and onion, chicken and mushroom, and beef and ale.
  • Select from cheese and onion, chicken and mushroom, and beef and ale.

Use a Colon after an Introduction

A colon (:) can be used after an introduction. For example:
  • There are just two more things we need to do: sign the contract and pop the cork.
  • The following personnel have been selected:

    1. Fred Bloggs
    2. Joe Bloggs
    3. John Doe

Ensure Your Introduction Can Stand Alone

When a colon is used in normal-looking text (like in the first example above), the introduction, i.e., the text before the colon, should be capable of standing alone. In other words, it should be an independent clause. Some strict grammarians maintain this ruling applies to all introductions preceding colons, even those which introduce bullet points and numbered points (like in the second example above).

For Vertical Lists, There Is More Leniency

When a vertical list is being introduced (typically, a bulleted list or numbered list), it is more acceptable to use an introduction which does not stand alone. For example:
  • A number of people have been selected. They are:

    1. Fred Bloggs
    2. Joe Bloggs
    3. John Doe
(Be aware that some of your readers might view this as sloppy writing.)

While such an introduction is widely accepted for a vertical list, for normal text, the colon would be wrong. For example:
  • A number of people have been selected. They are: Fred Bloggs, Joe Bloggs, and John Doe.
  • A number of people have been selected. They are Fred Bloggs, Joe Bloggs, and John Doe.

Watch Those Colons before Lists in Normal Text

Here are two more examples with standalone introductions:
The following points were noted as a result of the fire-safety
survey:

a. Fire exits blocked by empty PC boxes.
b. Batteries dead in smoke detectors.
c. Waste-paper bins used as ashtrays.
The winners are the following: John, Sarah, and Simon.
The introductions above might feel incomplete because the word following suggests there is more to come. However, they are complete. They both include a subject and a predicate. Compare the last example with this:
  • The winners are: John, Sarah, and Simon.
    • (The colon is wrong. The introduction before the colon does not contain a subject and a predicate; i.e., it cannot stand alone. This is unacceptable in normal text.)
  • The winners are John, Sarah, and Simon.
    • (This is correct with no colon.)
Where possible, try to keep your introductions as standalone clauses. However, you will encounter plenty of circumstances when a full standalone clause is inappropriate. Below are some examples of non-standalone introductions which are deemed acceptable:
Contact us by:

1. Phone: 01908 311267
2. E-mail: colin@lion-tamers.co.uk
3. Fax: 01908 311269
  • Beer: the cause of, and solution to, all of life's problems. (Homer Simpson)
  • Diplomacy: the patriotic art of lying for one's country. (Ambrose Bierce)
  • The English country gentleman galloping after a fox: the unspeakable in full pursuit of the uneatable. (Oscar Wilde)

See Also

How to use colons to extend sentences Colons in references Colons with bullet points Colons with quotations