1) BEFORE A SERIES OR LIST
Colons are used to introduce a series or list only after a complete sentence. When the series immediately follows a verb or preposition, do not use a colon.
Example:
Incorrect: Our five travel choices are: the Bahamas, Hawaii, Mexico City, Acapulco, and Peoria.
Correct: We have five travel choices: the Bahamas, Hawaii, Mexico City, Acapulco, and Peoria.
Incorrect: They were interested in: one brass bed, two lace pillows, one afghan comforter, and a chamber pot.
Correct: They were interested in the following items: one brass bed, two lace pillows, one afghan comforter, and a chamber pot.
2) BETWEEN INDEPENDENT CLAUSE
Use a colon to introduce a question or related statement following an independent clause. The second independent clause may or may not begin with a capital letter.
Example:
- She had only one thought: What was she going to do now?
- I know the answer: reverse the two equations.
3) TIME
Colons are used to express time in figures. Do not use the words o’clock after the figures. However, expressions such as noon, in the afternoon, A.M., P.M., and midnight can be used.
Example:
- 10: 30 a.m.
- 5: 35 p.m.
- 12: 00 midnight
- 8: 30 in the morning
4) FORMAL AND BUSINESS COMMUNICATIONS
Colons follow the salutation in a formal or business letter, report, memo, or other type of business communication.
Example:
- Dear Mr. David:
- Dear Buyer:
- Dear President West:
- To the Research Staff:
- To All Managers:’
- Attention Union Members:
