Preceding a List

A common use for the colon is to precede a list. However, do not use a colon when the list is a necessary part of the sentence. In grammatical terms, a colon should not be placed between a verb and its complement, or a preposition and its object. In other words, do not use a colon to break up words that function together.

✘ Now that she has her MBA, the dream cars that she is interested in buying are: a BMW Z3, a Porche Speedster 911, or a Volkswagen Carmen Ghia.

(Colon separates the verb “are” and its complement “BMW Z3 Roadster,” etc.)

✘ Now that she has her MBA, her dream car wish list consists of: a BMW Z3, a Porsche Speedster 911, or a Volkswagen Carmen Ghia.

(Colon separates the preposition “of” and its object “BMW Z3 Roadster,” etc.)

✓ Now that she has her MBA, she intends to buy her dream car: a BMW Z3, a Porsche Speedster 911, or a Volkswagen Carmen Ghia.

Introducing Quotations

Colons should be used sparingly, especially as a means of introducing single sentence quotations. Rather, try to integrate the quotation into the syntax of your sentence. For example, although the following sentence is grammatically correct, the style is awkward.

Hazel Motes firmly believes in his automobile: “No man with a good car needs to be justified.”

The colon stops the sentence too abruptly. In the second version of the sentence, the syntax, and hence the ideas, flow more naturally.

✓ As Flannery O’Connor’s Hazel Motes remarks, “No man with a good car needs to be justified.”

On the title page of a book, the main title and subtitle are often set apart by the spacing on the page or the use of a different typeface. When citing such two-titled works in your essay, use a colon to separate the title parts.

✓ Wheels: The Story of the Car in Canadian History.

Taking the Place of Coordinating Conjunctions

A semicolon should not appear before coordinating conjunctions – linking words such as and, or, but, so, for, yet – which are preceded by a comma. However, a semicolon may take the place of one of these joining words, lending equal conceptual weight to the linked expressions.

✘ The Rebel Alliance fought valiantly; but they could not defend the Echo Base against the Imperial assault.
(The “but” should be preceded by a comma.)

✓ Han Solo is the best blockade runner in the Outer Rim Territories; Luke Skywalker is the best starfighter in the galaxy.
(The semicolon takes the place of coordinating conjunction “and.”)

Conjunctive Adverbs and Transitional Phrases

When a conjunctive adverb (e.g., however, nevertheless, therefore, thus) or a transitional phrase (e.g., for instance or in fact) appears between two independent clauses, it must be preceded by a semicolon, and is usually followed by a comma.
✓ Luke learns about the Force from Obi Wan Kenobi; however, he is not told that his father has chosen to follow the Dark Side.

✓ Princess Leia senses a mystic connection with Luke Skywalker; in fact, she is his sister.

Exceptions

Generally speaking, when using a semicolon, both parts of the sentence must carry equal grammatical weight; they must both be able to stand independently as a sentence if the semicolon is removed. However, there is one exception to this rule. While semicolons are never used to introduce a list, they are conventionally used to separate lengthy items in a list, especially when individual items contain internal punctuation (i.e., a comma). This convention saves confusion about which words logically belong together.

✓ The X-Wing Starfighter is equipped with state-of-the-art weaponry: four laser cannons, one on each wing tip; two proton torpedo launchers, placed at mid-hull; and a sophisticated targeting computer.