A Military Writer's Handbook
Punctuation

The Colon

Most writers understand that a colon is used primarily to introduce a list, but this has led to the faulty practice of introducing any list of items in a sentence with a colon. To use this piece of punctuation correctly, you need to be aware that the colon introduces only certain kinds of lists: items that are added on to an independent clause, which can stand as a complete sentence.

  • Use a colon after an independent clause to introduce a list of terms

    The armed forces organized themselves on six key requirements: readiness, sustainability, jointness, reorganization, modern high-tech equipment, and international cooperation.

  • Use a colon after an independent clause to introduce a list of phrases

    • Half a century ago, NATO members agreed to be guided by the four freedoms of the wartime alliance: the freedom from want, the freedom from fear, the freedom of worship, and the freedom of assembly.

  • The most abrupt piece of punctuation, the colon is also used at the end of a sentence to draw attention to a significant word or phrase. Use a colon after an independent clause to add a clarifying detail

    • Canadian governments are keenly aware that they must contribute to the defence of North America, or they run the risk of having the United States shoulder the burden alone, usurping the final pillar of any national sovereignty: self-defence.

  • Use a colon after an independent clause to introduce a quotation, especially a block quotation

    Having defined its task as peacekeeping and not peacemaking, the UN discovered that its role in Yugoslavia was seriously undermined: "there was no peace to keep, because hostilities had just started."

Help! Consider the typographical appearance of the colon: it is composed of two periods, stacked. Its form thus determines how it should be used: in the same way a period is used, after a complete sentence. Whenever you use a colon, cover up the top "dot" to create a period. As with the period, the words that come before a colon should make up a complete sentence. If they do not, then the colon is incorrectly used. If the words do form a complete sentence, and you are introducing a list, adding a clarifying point, or introducing a quotation, then the colon should be correct.

Conventional Colons