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Style Manual

Colons

A colon draws the user’s attention to text that follows. Add colons only if essential. Use them to introduce examples, contrasts, lists and block quotes.

Limit colon use

Use a colon only if you are sure it is needed. Incorrect use creates confusion for users.

Introduce examples and contrasts with colons

Use a colon to:

  • introduce a word, phrase or clause that provides more detail
  • introduce a question
  • give an example
  • summarise or contrast with what comes before it.
Example

Use correct spelling: check a dictionary if you need to.

Our work is about answering this simple question: how?

We’ll have to use a stronger tool: sanctions.

This is the guiding principle for our workplace: collaboration.

The committee found there was only one possible explanation: fraud.

A sentence fragment can come before the colon if the fragment can stand alone or if it’s introducing a bulleted list.

Example

Warning: strong winds forecast for Sydney today.

Start lists with a colon

Use a colon to introduce a list of words, phrases or clauses.

Example

Pick any 2 of the 3: low price, high speed, high quality.

The position has these requirements: strong communication skills and experience across content management platforms.

We need to:

  • check Appendix A of the report
  • ask Mary about the final chapter of her book
  • rewrite our introduction.

Don’t include a colon when the list flows on as part of a full sentence. This is a common error.

Correct

Pick any 2 of low price, high speed and high quality.

The requirements for the position are strong communication skills and experience across content management platforms.

Incorrect

Pick any 2 of: low price, high speed and high quality.

The requirements for the position are: strong communication skills and experience across content management platforms.

Include the colon to restructure content into bulleted lists.

Example

The requirements for the position are:

  • strong communication skills
  • experience across content management platforms.

Use lower case following a colon in most cases

Start the word after the colon with a lower case letter unless:

  • the word that follows the colon is a proper noun
  • the text after the colon is a question that is a complete sentence.
Correct

We had to write 66 reports: it took months.

The commander was confident: Special Air Service Regiment had enough ammunition.

Incorrect

We had to write many reports: It took months.

The commander was confident: special air service regiment had enough ammunition.

After a colon, capitalise the first word of questions that are complete sentences. This makes it clear that the question mark applies only to the text after the colon.

Like this

The election was fought on a simple question: Which party had the best economic credentials?

Not this

The election was fought on a simple question: which party had the best economic credentials?

If the colon introduces a series of sentences or questions, use a lead-in and colon to introduce them in a bulleted or numbered list.

Example

They answered the question:

  • They wrote 23 reports.
  • Each report took 11 days to write.

Start subtitles of books and articles with a colon

Use a colon before the subtitle of a book or article. Follow the colon with a lower case letter, unless it’s a proper noun.

Example

Teaching in Australia: a deep dive into the education system

Stanovich KE (1986) ‘Matthew effects in reading: some consequences of individual differences in the acquisition of literacy’, Reading Research Quarterly, 21(4):360–407.

Do this when writing about a book or article and also when referencing one.

Introduce block quotes with colons

Use a colon to introduce a block quote. Block quotes should also be coded with the HTML <blockquote>  element.

Example

For example, Manthorpe (2019) stated:

Short sentences are easier to read because they limit the scope of an idea. But most readers like the variety and rhythm of a mixture of sentence lengths. For most readers, aim for an average sentence length of 15 words per sentence.

Write mathematical ratios with a colon

Use a colon to give a mathematical ratio. Don’t put a space after the colon.

Example

The government proposes a 50:50 split.

The cost-benefit ratio will be 7.5:1.

Release notes

The digital edition consolidates information about colons that appeared in different parts of the sixth edition.

The digital edition excludes advice about colons in multi-level lists as it does not recommend using them in the digital environment.

The digital edition recommends using a colon for a precise reference to time. The use of a colon as the separator reflects a shift in contemporary Australian usage. Sources cited as evidence on that topic support this change.

The Content Guide had advice about colons in relation to lists only.

About this page

References

American Psychological Association (2020) ‘Mechanics of style’, Publication manual of the American Psychological Association,7th edn, American Psychological Association, Washington DC.

Dixon JC and Bolitho B (2005–2019) Course notes and exercises: Editing and proofreading for the workplace, Centre for Continuing Education, Australian National University, Canberra.

European Commission (2020) ‘2: Punctuation’, English style guide: a handbook for authors and translators in the European Commission, European Commission, accessed 6 May 2020.

Murphy EM with Cadman H (2014) Effective writing: plain English at work, 2nd edition, Lacuna, 2014.

Oxford University Press (2016) ‘Punctuation’, New Oxford style manual, Oxford University Press, Oxford.

Seely J (2001) Oxford everyday grammar, Oxford Paperback Reference.

Stilman S (2004) Grammatically correct, Writer’s Digest Books, 2004; revised and updated, 2010.

Truss L (2003) Eats, shoots and leaves: the zero-tolerance approach to punctuation, Profile Books, London, 2003.

University of Chicago (2017) ‘Punctuation’, Chicago manual of style, 17th edn, University of Chicago Press, Chicago.

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