9.3: Colon

Think of the colon as the Vanna White of punctuation: it’s used almost exclusively to present the sentence’s really important content. A colon can introduce a list, a direct quotation, or an explanation (see, for example, the first sentence above). A colon almost always needs to follow a complete thought:

• The treasures he found were impressive: rubies, diamonds, and the original VW Beetle. [ complete thought followed by list ]
• Herman Melville begins his novel Moby-Dick with a simple yet intriguing sentence: “Call me Ishmael.” [ complete thought followed by direct quotation ]
• The candidate lacks one of the most essential traits of an effective leader: integrity. [ complete thought followed by explanation ]

You can’t use “such as” or a “be” verb like “is” or “are” in front of a colon. Like the semi-colon, it prefers to work alone.

• Many school districts struggle to fund important programs such as: music and art. [ incorrect —colon disrupts the flow ]
• Many school districts struggle to fund important programs such as music and art. [ correct ]
• My favorite pizza toppings are: peppers, onions, and ham. [ incorrect — colon disrupts the flow ]
• My favorite pizza toppings are peppers, onions, and ham. [ correct ]

Be careful when writing letters. A comma after “Dear Jane,” is friendly; a colon after “Dear Jane:” means business.