Colons have two primary uses: to introduce lists (as we've just done) and in subtitles. Here are examples of each use.
Colons are used to introduce lists of information that clarifies the earlier portion of the sentence. Importantly, the sentence that introduces the list must be a complete, independent sentence.
- Please bring: pencils, paper, and erasers.
- I subscribe to: Vogue, Newsweek, Esquire, and Ebony.
- The author says: "The colon is often misused."
The error in each of these sentences is that the writer tries to use a colon after a group of words that does not form a complete, independent sentence.
- Please bring pencils, paper, and erasers. OR
- Please bring the following supplies: pencils, paper, and erasers.
- I subscribe to Vogue, Newsweek, Esquire, and Ebony. OR
- I subscribe to four magazines: Vogue, Newsweek, Esquire, and Ebony.
- The author says, “The colon is often misused.” OR
- The author says important things about grammar: “The colon is often misused.”
Notice that you have at least two options for correcting a sentence that misuses a colon. You may either remove the colon altogether (as the first corrections in each example do) or revise the words before the colon into complete, independent sentences.
Colons are also used in titles with two parts: the main title and the subtitle. The colon follows the main title to introduce the subtitle. The main title need not be a complete sentence for a colon to be used. For example, the following title uses a colon:
Teaching Online: A Practical Guide