What are the Correct Uses of the Colon in Grammar?

The Colon in Business Communication

• The colon often appears in business communications. Use a colon, not a comma,

  after the greeting in a business letter. For example, place it after "Dear Mr. Jones." In a memo, use colons after each heading. For example, write: "To: J. Jones."

  Email templates, like memo templates, normally use a colon after each heading. For example, "Re: Contract No. 34567."

The Colon With Lists

• Use a colon after an independent clause introducing a list. For example, write: "He sold everything that he owned: land, mule, lumber and machinery." In report style, use a colon to introduce lists that show each item on a separate line. A number or bullet is frequently assigned to each item on a list.

The Colon With Quotations

• You can use a colon instead of a comma to introduce a long quotation. For example: "He began his argument by summarizing his opponent's view: 'My opponent has promised that if elected he will cut taxes and increase employment.'" Always use a colon to introduce a quotation in blocked style. After the introductory statement and colon, start a new line, indenting the entire quotation to set it apart. A quotation is usually blocked if it consists of three or more lines.

Colons With Numbers

• The colon separates numbers in several ways. Use the colon between hours and minutes and between minutes and seconds for time. For example, write: "9:20 p.m." For races, use colons in this way: "The winner's time was 3:21:30." This means three hours, 21 minutes and 30 seconds. Separate the chapter and verse in Bible references with a colon: "Genesis 1:1."

The Colon to Connect Ideas

• A colon can connect two related ideas. You can choose to connect two independent clauses with a colon instead of a semicolon if the second clause explains, summarizes or gives an example. Write, for example: "He had completely lost his nerve: He would never again appear as an actor." You can also use a colon to connect an independent clause to a logically related fragment that follows: "He had everything he needed to open his store except one thing: a good location." Note that the first portion must be an independent clause.

The Colon in Academic Work

• The colon has special uses in book titles and bibliographies. Use a colon to separate the subtitle from the title of a book. Write: "The Foot: Its Function and Anatomy." Depending on your style sheet, you can also separate the city of publication from the publisher's name with a colon: "San Mateo, California: Mateo Press, 2008."