The colon is used primarily to introduce or call attention to the words that follow it. The colon is also used between clauses when the second clause summarizes or explains the first, or in certain situations to indicate a separation between specific elements.
1. Use a colon after an independent clause to introduce or direct attention to a list, an appositive, or a quotation.
List: The winning numbers are as follows: four, five, nine, and eleven.
Appositive: Every day my mother packed my lunch: a peanut butter sandwich, two cookies, and an apple.
Quotation: Consider carefully the words of a Zen proverb: "When the mind is ready, a teacher appears."
2. Use a colon between independent clauses if the second clause summarizes, explains, or gives an example for the first clause.
After the service, the women performed a graceful task: they lit the tiny candles one by one.
Our committee received the board's recommendation: Finalize the budget tonight!
3. Use a colon to separate certain elements, such as after the salutation in a formal letter, between hours and minutes to indicate time, between numbers to show proportions, between a title and subtitle, and between the city and the publisher and date in bibliographic entries.
The ratio of students to teachers was 22:1.
Grammar and Style: A Handbook on College Writing
New York: McGraw-Hill, 1988
|Avoid common errors using the colon.
A colon must be preceded by a full independent clause. Therefore avoid using it between a verb and its object or complement, between a preposition and its object, and after such as, including, or for example.
For example, the following uses of the colon are incorrect:
Some of the colors used in the flags are: red, orange, blue, and black. (Incorrect)
The homework consisted of: four pages of dictionary definitions. (Incorrect)
He loves spring flowers such as: the daffodil, daisy, and sunflower. (Incorrect)