Many people are confused about using colons, but their function is actually quite straightforward. Think of it as a flashing arrow that points to the information following it. When a colon appears in a sentence, it usually gives the silent impression of “as follows,” “which is/are,” or “thus.”There are three types of muscle in the body: cardiac, smooth, and skeletal.

The colon in this sentence signals that you are about to learn the names of the three types of muscles the sentence already mentioned. We might silently read the sentence this way.

• There are three types of muscle in the body (and they are): cardiac, smooth, and skeletal.

Colons are often used with lists, as in the example above. They can also be used to signal further clarification.

• We have two options here: stay and fight, or run like the wind.

One might silently read this as:

• We have two options here (and they are as follows): stay and fight, or run like the wind.

Colons can also introduce a quotation:

• He ended with the immortal words of Neil Young: “Rock and Roll can never die.”

Colons Separating Independent Clauses

A colon can be used to separate two independent clauses when a) the second clause is directly related to the first clause (not just vaguely related) and b) when the emphasis is on the second clause. While you can also use a semicolon or a period between two independent-yet-related clauses, the colon is a little softer than the period, but a little harder than the semicolon.

In British English, the word following a colon is not capitalized unless it is a proper noun or an acronym. In American English, styles differ, but it is best to capitalize the first word after a colon if what follows forms two or more complete sentences.

Misuse of Colons

A colon should not separate a noun from its verb, a verb from its object or subject complement, a preposition from its object, or a subject from its predicate.

To illustrate, here is one of our sentences from above rewritten incorrectly.

Putting the colon here separates the verb are from its subject complements (cardiac, smooth, and skeletal).

The colon should be removed from this sentence because it separates the preposition to from its objects (Rome, Israel, and Egypt). To write this sentence correctly, the colon should be removed.