After receiving an email with the subject line “Save a child’s life with a banana,” fundraising guru Tom Ahern issued a challenge in his e-letter to write email subject lines ending “with a banana.” It sounded like fun, so I did!

This post otherwise has nothing to do with bananas. It’s about colons and semicolons.

The rules for colons and semicolons are simple. There are no judgment calls to speak of. If you have trouble with colons and semicolons, it’s probably because you’ve learned rules that are not rules at all.

Colons

The main use for colons in ordinary prose is to introduce a list, an instance, or an example.

The cat jumped a foot in the air when it saw the threatening object: a banana.
Please bring the following items: a banana, a barrel of monkeys, and a rope.
We encountered an unexpected obstacle: The bananas were still green.

You can use a colon only when the part of the sentence before the colon is a complete sentence. Use a colon when you can substitute the word “namely.” If you can’t, don’t use a colon.

The items found at the site include a banana, a barrel of monkeys, and a rope.

Many style guides also have us use colons to introduce lists laid out as bulleted or numbered lists. Other uses for colons include dividing the subtitle of a document from its title and the hour from the minutes. You’ve had those down since fourth grade, right? If not, try this list.

Semicolons

Semicolons are similarly easy; they have only two main uses.

1. Use a semicolon to separate independent clauses within one sentence.

I hate bananas; they’re pasty and sweet.
I hate bananas; however, I love fried plantains.

In these sentences, the two clauses on either side of the semicolon, though short, could each stand alone as a sentence.

2. Use semicolons to separate items in a list when one or more list items are already punctuated by commas.

The grocery stocked the usual Cavendish bananas; a variety of smaller dessert bananas, including lady fingers, ninos, and manzanos; and cooking bananas, including plantains and burros.

You may have learned some non-rules: for example, that you use semicolons when list items are long, when the list is introduced with a colon, or when the list items are numbered or lettered. None of those are true.

All that matters is whether the list items contain commas.

The banana experts agreed on several points: (1) that the smallest bananas pack the largest flavor, (2) that medium-sized bananas are generally easiest to harvest and pack, and (3) that large bananas are not likely to gain large share in North American markets.

There you go: colons and semicolons with a banana (or several). Any questions? Thoughts about bananas?