What’s the difference? Do we need them?
The English writer Julian Barnes recently told a story about the Irish writer Frank O’Connor. O’Connor was once stopped on the road west of Kinsale by a man who said: “I hear you’re a famous writer. I’d like to be a famous writer too, but it’s bloody hard. The comma and the apostrophe are easy enough, but the semicolon is the very divil.” In case your feelings about punctuation are similar, here’s the basics: the semicolon is the one with a dot and a comma on top of each other, like this; and the colon is the one with two dots, like this:
Semicolons (like commas, periods, dashes, etc.) are rest and breathing markers. If a comma is a quick pause before we continue with a sentence, and a period tells us to come to a full stop (that’s what it’s called in Britain—a full stop), a semicolon is a halfway house—more than a comma, not as final as a period. In the previous paragraph, the semicolon is being used in that way, separating the long phrase describing how a semicolon looks from the next one (about the colon).
If semicolons can be said to have a specific, official job, it’s to be used instead of commas in lists with a lot of potentially confusing components, viz.:
She found that in order to do the best job she could, she had to put together long lists of intriguing, relevant websites; thoughtful, wide-ranging references from books and magazines; and witty, apposite quotations from every possible contemporary source.
You can see here that while you could probably make do with commas where the semicolons are, this could quickly feel long and messy. Thank heavens for the semicolon!
Colons have a specific, official job: telling you that a definition or a list of components or ingredients is coming up. The colon in the previous sentence is doing what colons are born to do—it’s saying, “Pay attention—I’m about to tell you the point of this whole thing.” If we took the sentence discussed in the semicolon section and used it as a recipe for anxious bloggers, the colon could play its part (although, admittedly, you could leave the colon out altogether here and the sentence would still make sense).
Links for a great site should include: intriguing, relevant web pages; thoughtful, wide-ranging references; witty, apposite quotations.