The Colon

The colon (:) seems to bewilder many people, though it’s really rather easy to
use correctly, since it has only one major use. But first please note the
following: the colon is never preceded by a white space; it is always followed
by a single white space in normal use, and it is never, never,
never followed
by a hyphen or a dash — in spite of what you might have been taught in school.
One of the commonest of all punctuation mistakes is following a colon with a
completely pointless hyphen.

The colon is used to indicate that what follows it is an explanation or
elaboration of what precedes it. That is, having introduced some topic in more
general terms, you can use a colon and go on to explain that same topic in more
specific terms. Schematically:

More general: more specific

A colon is nearly always preceded by a complete sentence; what follows
the colon may or may not be a complete sentence, and it may be a mere list or
even a single word. A colon is not normally followed by a capital letter in
British usage, though American usage often prefers to use a capital. Here are
some examples:

Africa is facing a terrifying problem: perpetual drought.

[Explains what the problem is.]

The situation is clear: if you have unprotected sex with a stranger, you
risk AIDS.

[Explains what the clear situation is.]

She was sure of one thing: she was not going to be a housewife.

[Identifies the one thing she was sure of.]

Mae West had one golden rule for handling men: “Tell the pretty ones
they’re smart and tell the smart ones they’re pretty.”

[Explicates the golden rule.]

Several friends have provided me with inspiration: Tim, Ian and, above
all, Larry.

[Identifies the friends in question.]

We found the place easily: your directions were perfect.

[Explains why we found it easily.]

I propose the creation of a new post: School Executive Officer.

[Identifies the post in question.]

Very occasionally, the colon construction is turned round, with the
specifics coming first and the general summary afterward:

Saussure, Sapir, Bloomfield, Chomsky: all these have revolutionized
linguistics in one way or another.

Like all inverted constructions, this one should be used sparingly.

While you’re studying these examples, notice again that the colon is
never preceded by a white space and never followed by anything except a single
white space.

You should not use a colon, or any other mark, at the end of a heading
which introduces a new section of a document: look at the chapter headings and section headings in the present document. It is, however, usual to use a colon after a word,
phrase or sentence in the middle of a text which introduces some following
material which is set off in the middle of the page. There are three consecutive
examples of this just above, in the second, third and fourth paragraphs of this
section.

The colon has a few minor uses. First, when you cite the name of a
book which has both a title and a subtitle, you should separate the two with a
colon:

I recommend Chinnery’s book .

You should do this even though no colon may appear on the cover or the title
page of the book itself.

Second, the colon is used in citing passages from the Bible:

The story of Menahem is found in II Kings 15:14–22.

Observe that, exceptionally, the colon is not followed by a white space in
Biblical references.

Third, the colon may be used in writing ratios:

Among students of French, women outnumber men by more than 4:1.

In formal writing, however, it is usually preferable to write out ratios in words:

Among students of French, women outnumber men by more than four
to one.

Fourth, in American usage, a colon is used to separate the hours from
the minutes in giving a time of day: , (A). British Eng
lish uses a full
stop for this purpose: , .

Finally, the colon is used in formal letters
and in citing references to published work.

Copyright © Larry Trask, 1997

A colon introduces an element or series of elements that illustrates or amplifies the information that preceded the colon. While a semicolon normally joins two independent clauses to signal a close connection between them, a colon does the job of directing you to the information following it.

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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.”

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.”

READ MORE: Capitalization After Colons

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.

A dolphin is not fish: it is a warm-blooded mammal.

The research is conclusive: climate change is a reality.

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.

I have several plans for my immediate future: First, I’m going to win the lottery. Second, I’m going to buy a unicorn. Third, I will marry Brad Pitt.

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.

The three types of muscle in the body are: cardiac, smooth, and skeletal.

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

When I graduate, I want to go to: Rome, Israel, and Egypt.

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.

When I graduate, I want to go to Rome, Israel, and Egypt.