Colons and semicolons are the indie rock of punctuation marks. They’re not mainstream-popular like the period. They aren’t obvious and eager-to-please like the exclamation mark. They’re not everywhere like the comma. But the colon and the semicolon have passion. They’re quirky, snobby, and sometimes prickly. These I-was-using-them-before-they-were-cool punctuation marks are like Jay and Michael Aston of Gene Loves Jezebel: They’re brothers, but they not twins, and they do not always get along.
The right way to use a colon: Two little dots that can say so much
The colon has a number of fiddly uses. It introduces an item or list, separates closely related independent clauses, introduces longer quotations, and introduces bulleted or numbered lists. It’s also frequently used following a greeting in more formal correspondence.
A colon can be used in place of a period or a comma and conjunction between two independent clauses when the second sentence emphasises, illustrates, or explains the first.
I didn’t end up going to Sisters of Mercy show: I was out of eyeliner.
When used this way, you can “read” a colon as something like “because” or “thus.”
Here is what it looks like when a colon is used to introduce a list:
Neutral Milk Hotel has three main influences: early Pink Floyd, The Minutemen, and The Diary of Anne Frank.
A colon can be used after “the following” or “as follows” but not after “for example,” “including,” “such as,” or “that is.” In those cases, use a comma.
A colon is often used after a speaker’s name to present dialogue or a quotation:
Like The Mountain Goats’John Darnielle said in “The Best Ever Death Metal Band in Denton”: “When you punish a person for dreaming his dream, don’t expect him to thank or forgive you.”
When you are quoting something longer, use a colon. Do the same when you are presenting a list that is numbered or uses bullet-points, as follows:
Here is the track listing of Big Black’s seminal 1986 album Atomizer:
1) Jordan, Minnesota
2) Passing Complexion
3) Big Money
5) Bad Houses
6) Fists of Love
7) Stinking Drunk
8) Bazooka Joe
9) Strange Things
10) Cables (Live)
People sometimes use a colon after a greeting in correspondence, famously after “To Whom it May Concern.” This usage was cool in the past, but now it seems overly formal, stuffy, and try-hard enough to be ironic.
Dear NME: I am still angry about your lukewarm review of The Stone Roses’ first album.
All the cool people add a spaces after a colon. Capitalising after a colon is not cool, except in a few situations. If you’re introducing a list, capitalise the first word after the colon only if it’s a proper noun.
If the second phrase after the colon can stand as a complete sentence, you generally don’t capitalise it, but some people maintain that you can capitalise it if it’s a longer sentence. (Some people think Pablo Honey is a better album than OK Computer, but that doesn’t make them right.) [Editor’s note: This site’s style is to capitalise standalone phrases after a colon, so. Also, OK Computer is overrated.]
If you want to dig as deeply into the colon as you dig into the crates at your local used record shop, consider the double colon. It looks like this: “::” and is used in analogies, famously on SAT tests. When writing an analogy, instead of writing: “W is to X as Y is to Z,” you can write “W : Z :: Y : Z” As in the following analogy:
Dag Nasty : 1986 :: My Chemical Romance : 2003.
Double colons are also used in some programming languages too, but I can’t tell you how because I am not a nerd.
How to use a semicolon: We should probably get rid of them entirely
The semicolon has three uses: linking independent but closely related clauses, combining sentences with a conjunctive adverb followed by a comma, and replacing commas in lists if the comma would be confusing. Semicolons are not used to link an independent and a dependent clause like the colon or the comma.
If periods are too mainstream for you, you can use either a colon or a semicolon to separate two closely related independent clauses. It gets a little hair-splitty when you try to determine which to use when though. This mixed-up state of affairs is partly because these two marks tend to be used differently in the U.K. and the U.S., but overall, the semicolon reads as a little more conversational. The colon is a bit more formal. Compare the following:
That was the best show ever: Galaxie 500 played with its original lineup.
That was the best show ever; Galaxie 500 played with its original lineup.
Subtle, right? But if you’re into semicolons, you have to be comfortable with ambiguity.
Things clear up a lot when you get into conjunctive adverbs like “moreover,” “nevertheless,” “however,” and “also.” These should include a semicolon, as follows:
She put on a Moby CD; consequently, I asked her to leave my home.
The semicolon’s real starring moment comes when you are presenting a list that would be confusing if you separated it with commas, as in the following:
The lineup of Joy Division was Ian Curtis, vocals; Bernard Sumner, guitar and keyboard; Peter Hook, bass; and drummer Stephen Morris.
A final, important note on colons
If you are old enough to understand the musical references I have been making, you should schedule a colonoscopy every five years.