Colons

search our site by Craig Shrives

What Are Colons? (with Examples)

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 to 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:

• He joked: "Curiosity killed the cat, but for a while I was a suspect."
(You could also have used a comma here (instead of colon). If the introduction to the quotation or the quotation itself is a dependent clause, you can use a colon.)

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 Colons Are Important

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.

Key Points

Printable Test