Semicolon vs. Colon: Understanding the Difference

Two punctuation marks that often get confused are the semicolon and the colon. Knowing the difference between these two will help you express yourself more clearly when writing, as they have different functions.

The main difference between the two punctuation marks is that a semicolon (;) is only used to separate independent clauses that are related, whereas a colon (:) is primarily used to introduce lists and quotations, among other uses. A colon can also be used to separate independent clauses.

This article aims to clarify the difference between the two punctuation marks, with examples to simplify the idea for you.

The function of a semicolon

The semicolon's primary use is to separate independent clauses while still denoting that they are related. Very rarely, you can also use a semicolon to separate items in a list. Note that the semicolon gives equal importance to the clauses (or list items) it separates.

Let's take a look at exactly what that means.

What are independent clauses?

Before we can discuss independent clauses, we must first define the term "clause" to avoid any confusion. A clause is a string of words including a subject and a predicate, forming part of a sentence. Note that according to grammatical organization in English, a clause ranks lower than a sentence.

To further simplify, think of a clause as a part of the sentence with its own subject-verb unit. Do not confuse clauses with phrases, because a phrase does not include a subject-verb unit.

Independent clauses are two parts of a sentence that the writer considers equally important. One defining feature of independent clauses is that you can use them as standalone sentences as well.

Example:

• My big sister kicks the ball; she doesn't score a goal.

Here sister-kick, and she-score are the two subject-verb units of two clauses in the same complex sentence. You can also turn both clauses into standalone sentences.

So why use a semicolon instead of a colon? Simply because the semicolon demonstrates the close relationship between the two clauses and establishes that they are equally important.

Using semicolons to separate items in lists

Although it is not as common as the previously mentioned usage, a semicolon can be used to separate items in lists. Usually, a comma (,) is used when listing items in a series or a list. However, if the writer wishes to emphasize that the items rank equally, a semicolon may be used.

You can choose to use a semicolon in this way in order to convey that the items in your series are of equal importance. This approach is often used when citing studies as source material or naming multiple authors in an article.

Also, a semicolon can be used to separate items in a series if the items are phrases or clauses that contain commas. This approach is used to avoid confusion between the commas within the phrases and the commas separating them.

Example:

• I consulted with more than one law firm: Smith, Jackson, and Associates; Brown, Kenneth, Reed, and Jones; and The Ronald Group.

In the example above, the semicolons help the reader distinguish between the different law firms since each name contains commas to separate the partners' names.

The function of a colon

Now that you understand the function of a semicolon, it's time to move on to the colon (:). This punctuation mark has a variety of uses and I'm certain you're familiar with a few of them. Note that there is some overlap between the usage of a colon and a semicolon. I will elaborate on the difference later.

Adding emphasis

One of the most common uses of the colon is to add emphasis to a clause or phrase. If you think about it, you will realize that you typically take a short pause when reading, and a colon comes along.

Example:

• There was only one person who could save the patient: Dr. Albert.

Compare the sentence above with this: (Dr. Albert was the only person who could save the patient.)

As a reader, you'll notice that the first example (using the colon) adds some emphasis on "Dr. Albert," instead of mentioning the name casually as the subject of the sentence. Use this tool in your writing but use it sparingly.

Introducing lists, explanations, quotations, etc.

The most common way that writers use colons is to introduce something. This could be a list, paragraph, important information, or even quotations. This is also the use you are probably most familiar with as there is no confusion as to the purpose of the colon.

Examples:

• List: The ingredients are simple: butter, sugar, flour, salt, milk, and water.
• Quotation: Gandhi: "Be the change that you wish to see in the world."
• Explanation: By then I had only one goal: to lose weight before New Year's.

Separating independent clauses

This usage is where there is an overlap between the semicolon and the colon. I've already mentioned that you can use a semicolon to separate independent clauses that rank equally.

But what if you want to show the reader that the second clause is more important than the first? In other words, you want to add emphasis to the second clause. The solution is simple: use a colon.

When using a colon to separate independent clauses, the reader's focus is shifted toward the second clause. You can use this method to help establish that the two clauses are related while also emphasizing the importance of the second clause.

Example:

• I was devastated: I had never failed an exam before.

In timestamps, ratios, etc.

While some people prefer to write down units of time separated by a period (10.30 am), it is far more common to find units of time separated by a colon. Here are a few examples you're probably familiar with:

• I arrived at the party at 11:15 pm.
• [01:23:42]
• Add a water and vinegar solution of 10:1 into the bucket.

Variations in usage

There is a slight variation between American English and British English regarding the use of a colon. The difference is only regarding the capitalization of the first letter of the clause following a colon. British writers typically do not capitalize the first letter, whereas Americans do. Both rules are acceptable.

Note that a semicolon is not followed by a capitalized letter (unless otherwise dictated) in both American and British grammar.

Common mistakes and how to avoid them

As the semicolon vs. colon debate can get confusing for many beginner writers, there are a few common mistakes. The following are the most common mistakes you should make an effort to avoid, including the correct usage in each case.

Using capitals after a semicolon

As I've mentioned earlier, neither American nor British grammar rules call for the capitalization of the first letter after a semicolon.

• Wrong: I try to drive cautiously; It only takes the blink of an eye for an accident to happen.
• Right: I try to drive cautiously; it only takes the blink of an eye for an accident to happen.

Connecting dependent clauses

If the two clauses you want to write are not only related but dependent on each other, you should separate them with a comma instead of a semicolon. This is likely one of the most common ways the semicolon is misused.

• Wrong: After a long meeting at work; I was exhausted.
• Right: After a long meeting at work, I was exhausted.

Introducing lists using a semicolon

While a semicolon can be used to separate items in a list, do not get ahead of yourself and introduce the list using this punctuation mark.

• Wrong: The ingredients were simple; beef, salt, pepper, and onions.
• Right: The ingredients were simple: beef, salt, pepper, and onions.

Separating subjects and verbs with a colon

Many beginner writers assume that they can use the colon to add a pause mid-sentence. Often, they incorrectly find themselves separating the units within a clause. Here is an example of that mistake:

• The children said they wanted: candy, toys, and balloons.

Instead of separating the verb want from its objects in the list, consider this more appropriate way of rewriting that sentence:

• The children said they wanted three things: candy, toys, and balloons.

Although the two sentences convey the same information, only the second example is grammatically correct.

Summarizing the major differences between semicolon and colon

The following table should help you remember the major differences between the two punctuation marks.

Conclusion

Despite being often misused and misunderstood, the differences between a semicolon and a colon are fairly simple. There are fewer uses for the semicolon, so you may want to familiarize yourself with its proper use first. To check if your sentences are correct after trying to apply these rules, you can also use an online grammar checker. This tool can help confirm whether you've used semicolons and colons correctly.

Hopefully, this article helps you to learn the purpose of each punctuation mark to better utilize them in your writing.

Header image by Maneesh.