Making Sense of Colons

A colon is a form of punctuation used at the end of a complete sentence to introduce a list or quotation, offer an explanation, or highlight information. It prepares the reader for the information that comes after it. 

Colons and Independent Clauses

A colon can join two complete sentences (independent clauses) when the second clause is connected to the first in terms of content. Capitalization of the first word in the second sentence varies according to the style manual used.

e.g., Exercise improves cognitive function in one key way (1):  It promotes the growth of new brain cells, thereby enhancing performance on memory tasks (2).

  1. Independent clause 

  2. Independent clause that offers an explanation of the key way.

Colons cannot be used when the writing before the colon is not an independent clause, as in the following sentence: "My favorite foods are: sushi, pizza, and nachos."

Colons and Emphasis/Explanation

A colon follows a complete sentence when introducing a list or quotation, offering an example or explanation, or emphasizing a point. 

e.g., Participants responded to the survey on three occasions (1): baseline, pre-treatment, and post-treatment (2).

  1. Independent clause

  2. List that clarifies the three occasion.

e.g., Mark Twain said it best (1): “Age is an issue of mind over matter. If you don’t mind, it doesn’t matter (2).” 

  1. Independent clause

  2. Quotation

  • Another common use of the colon is to separate a title from a subtitle. e.g., Star Wars: The force awakens.

e.g., Many participants indicated there was a positive outcome of exercising daily (1): reduced symptoms of anxiety (2). 

  1. Independent clause 

  2. Clarification of the positive outcome.