Thursday Tip: Using colons to link elaborations

Like the semicolon, the colon joins in one sentence two ideas or elements that might be expressed in separate sentences, strengthening the bond. The second elements are often definitions, elaborations, or embellishments. Here's an example from The Economist€™s '€œThe day after Super Tuesday':

He [Barack Obama] also snatched two prizes on the coast: tiny Delaware and, more symbolically, Connecticut.

Note that what follows the colon needn’t be a complete sentence. Consider another example from The Economist'€™s '€œSpeaking in tongues':

Indonesia's national language'a version of Malay called Bahasa Indonesia or just Indonesian'€”is unusual in that it is not the tongue of a dominant group: only about 3% of the population are ethnic Malays.

This usage is dubious. Some style guides (AP, for example) advise against using a dash and a colon in the same sentence.

Another function of the colon is to introduce a quotation (The minority leader delivered a harsh rebuttal:) or a list, either in text (Three areas for action:) or in bullets (see below).

But colons are often misused. Here are three don'€™ts:

• Don'€™t use a colon with for example (as in I'€™ve owned all types of pets, for example: cats, dogs, lizards, and ferrets.). The colon implies for example, which should be omitted.
• Don't separate a preposition from its object (as in Over the last year I've traveled to: Arizona, New York, and Cambodia) or a verb from its objects (For dinner he ate: soup, salmon, spinach, spaghetti, salad, and sherbet.).
• Don'€™t use colons where you should use semicolons, or semicolons where you should use colons. Colons imply a direct connection between two ideas--€”and what follows the colon is subordinate to what precedes it (think of it as shorthand for that is). And remember that semicolons should generally join two ideas only if both would be complete sentences taken alone, sentences that should be parallel when possible. (LeTourneau University has a quick primer on the basic differences between colons and semicolons if you need a refresher.)