Writing 101: Semi-Colons & Other Tricky Punctuation Marks

Punctuation can be surprisingly difficult, especially when it comes to lesser-used marks like semi-colons, dashes, and colons. When these marks are used incorrectly, readers are either distracted or confused.

Because this isn’t the experience we want for our readers, let’s take a look at some of these marks so we know when and how to use them.

Colons

A colon connects two related clauses. The first one introduces an element and the second one elaborates on it. When you’re using this mark, the first clause should be independent (meaning it could stand as a sentence on its own), but the second one doesn’t have to be.

Use a colon when…

1. Something needs emphasis.

There was only one rule in Mother’s house: don’t get caught.

2. The first clause introduces something that needs to be restated, refined, or listed.

She left me a list of chores: wash the dog, fold the laundry, and vacuum.

Additional Note:

The first word following the colon always starts with a lower-case letter, even when the second clause is independent.

Semi-Colons

This mark connects two related independent clauses (each clause could stand on its own as a complete sentence).

Use a semi-colon when…

1. You want to show a close relationship between two complete thoughts without using a conjunction.

Jack was always late; he simply had no concept of time.

2. Stylistically, you want a smoother reading flow without the full-stop interruption of a period (see the previous example).

3. (BONUS) You’re listing items that are being separated by commas. This is a formal, almost technical way of writing, so this usage is best reserved for nonfiction.

They ran tests in Miami, Florida; Dublin, Ireland; and Oslo, Norway.

Additional Notes:

If the narrative flows better with a firmer break between the two ideas, just use a period and create two sentences.

Jack was always late. He simply had no concept of time.

If you’re not sure when to use a colon or a semi-colon, remind yourself of their purposes. Want to set up a “here it comes” moment? Use a colon. Want to connect two related, complete thoughts without using two separate sentences? Opt for a semi-colon.

Em Dashes

This mark is a long dash (—) used to indicate an interruption or add emphasis.

Use an em dash when…

1. You want to insert additional information that has weight.

Jack was always late—every single time—and always had an excuse.

2. A character’s words or thoughts are being cut off or interrupted.

I took a deep breath. “You’re always—”
“Not now,” he snapped.

Additional Notes:

• Two hyphens together (–) aren’t the same as an em dash (—) so be sure you’re using the latter keystroke.
• Em dashes and parentheses are often used interchangeably to show an interruption, and there’s no hard-and-fast rule about their usage in this context. Generally, though, parentheses indicate more of an aside or an internal observation while em dashes accentuate what’s being stated.

A) Jack was always late (every single time) and always had an excuse.
B) Jack was always late—every single time—and always had an excuse.

If the interruption should be stronger or indicate higher emotion, a dash may be the better choice.

Commas

Commas are one of the most commonly used punctuation marks because they have a lot of applications, most of which are pretty straightforward. But I wanted to touch on two instances where they’re often misused.

Use a comma when…

1. You want to join two sentences into one. This is a good idea if you want to keep the pace moving, vary your sentence structures, or write dialogue with the character’s personal voice in mind. BUT, you can’t simply replace the period with a comma:

He wanted to stay, he knew it wasn’t a good idea. (incorrect)

When you connect two independent clauses with a comma, you end up with a run-on sentence—two complete sentences running together into one. In a run-on, the first complete sentence ends with a comma (not correct) and the second starts with a lower-case letter (also incorrect). To correctly connect two independent clauses with a comma, add a conjunction:

He wanted to stay, but he knew it wasn’t a good idea.

2. A pause is needed, particularly in longer sentences. Just be sure the comma doesn’t separate the subject of the sentence from its verb(s), as follows:

Beatrice drove like a maniac, and plowed right through the stop sign. (incorrect)

Think of the subject as a mom, and its verb is her needy toddler who’s hanging around all the time; the mom might lengthen the tether, but she’s always connected to her kid.

The same thing is true with the subject of a sentence (Beatrice) and its verbs (drove and plowed); for the sentence to read correctly and be clear, a comma can’t separate the two. In this case, the subject-verb connection trumps any potential pauses, and no comma should be used:

Beatrice drove like a maniac and plowed right through the stop sign.

But What About Personal Style?

This is a valid question. If your style lends itself to grammatical devices that are frowned upon, can you use them?

Technically, you can. And sometimes, you should. If your character is someone whose thoughts jump around or their speech tends to ramble into run-ons, you can write their words and thoughts to reflect that aspect of their personality. As you can see, I’m fond of starting sentences with contractions, which is on the list of Big No-Nos. But that’s how I talk, and in my blog posts, I want to sound like myself—not like a computer program.

But this bending of the rules only works when the decision is deliberate. If you break rules indiscriminately or randomly, you’re not making choices; you’re making mistakes. And that will read as amateurish and call attention to itself, distracting readers from the story you’re trying to tell.

Also, remember that rules of grammar exist to provide clarity for the reader. They help you convey exactly what you mean, without confusion. For this reason alone, it’s vital for you to know and understand the rules. Then you can decide when and if they should be broken.

Other Posts in This Series

Dialogue Mechanics
Effective Dialogue Techniques
Show-Don’t-Tell, Part 1
Show-Don’t-Tell, Part 2
Point of View Basics
Choosing the Right Details
Character Arc in a Nutshell