What Are Colons? (with Examples)

by Craig Shrives

Colons

A colon (:) is a common punctuation mark used:
  • To extend a sentence with an appositive (a renaming of something previously mentioned). For example:
    • He attributed his success one factor: luck.
  • To mark the end of an introduction (including before quotations). For example:
    • The inspection highlighted the following issues: too many coffee breaks, insufficient leadership, and too much non-work-related internet usage.
    • Philosopher Rene Descartes said: "I think; therefore, I am."
  • To separate elements in times, ratios, titles, and reference numbers. For example:
    • Arrange a meeting for 09:30 to discuss ways to improve the 1:4 ratio.

How Colons Are Used

Here is a quick overview on how colons are used:

(1) With an appositive at the end of a sentence. You can use a colon to expand on something previously mentioned in the sentence. (The words after the colon are called an appositive.) For example:
  • His influence is obvious in two buildings: the local church and pavilion.
  • (In this example, "the local church and pavilion" is the appositive of "two buildings," i.e., it's a renaming of "two buildings.")
Read more about using colons to extend a sentence.
Read more about appositives.

(2) After an introduction. You can use a colon with an introduction. For example:
  • The following were absent: Charles, Smith, Wainwright, and Dodds.
This includes introductions to quotations. For example: Read more about colons used for introductions.
Read about colons used with bullet points.

(3) In references, ratios, times, and titles. A colon can be used as a separator in references, ratios, times, and titles. For example:
  • Read Matthew 2:1 before 07:30.
  • (Here, there is a colon in a reference and a time.)
  • The ratio is 6:1 in Nottingham.
  • (The colon is in a ratio.)
  • "Grammar Rules: Writing with Military Precision" is the book of www.grammar-monster.com.
  • (The colon is in a title. )
Read more about colons used in references, times, and titles.

Other Punctuation Marks

Here is a slider with lessons to the other punctuation marks:

Why Should I Care about Colons?

Understanding how to use colons is a great tool to have in your writing kit. Using a colon to introduce an appositive at the end of a sentence is particularly useful for emphasizing an idea.

Here is the biggest error related to colons.

(Serious Error) Don't use a semicolon for an introduction.

A colon (often called a full colon) is used to introduce something. Do not use a semicolon (;) for this. This is quite a common error. For example:
  • The following were absent: Charles, Smith, Wainwright, and Dodds.
Here is another example featuring bullet points:
The inspection highlighted the following issues;
  • Too many coffee breaks.
  • insufficient leadership.
  • Too much non-work-related internet usage.

Read our main page about using colons.
Interactive Exercise
Here are three randomly selected questions from a larger exercise, which can be edited, printed to create an exercise worksheet, or sent via email to friends or students.

See Also

What is punctuation? What is an appositive? Colons to extend a sentence Colons for introductions Colons with bullet points Colons with references, times, and titles Colons with quotations Glossary of grammatical terms