How and When to Use a Colon (With Examples)

English has several kinds of punctuation, one of which is the colon (:). Contrary to popular belief, this punctuation mark’s function is easy to remember: it introduces additional information after a complete thought.

Nope, this colon post isn’t about your internal organs! Keep reading to learn the different functions of the colon as a punctuation mark and how to use it in a sentence.

What is a Colon?

A colon is a punctuation mark whose symbol resembles two periods on top of each other (:). It’s often known as an introductory punctuation mark. Colons show the audience pieces of information that clarify the previous statement. 

This punctuation mark is also helpful for separating independent clauses from quotations. You’ll find it in time expressions, Bible verses, and movie and book titles.

Colon comes from the Greek word kōlon. It means a part of a clause, verse, or limb, specifically a leg. Keith Houston, an author, stated that it originated in the third century BC in the Hellenic Egyptian city of Alexandria.

Use a colon to show dialogue or emphasis in your writing. You may also use it to introduce lists, clarify titles, and separate two independent clauses in sentences. 

Common Uses of Colon

Imagine the colon as an arrow pointing to an essential detail in the sentence. Here are the common usages of this punctuation mark.

Emphasizes Dialogue

In English grammar, a colon is a proper punctuation for showing dialogue. Write the speaker’s name, add the colon, then their statement. Check out the example below.

Mike: Graduate students need at least one mentor to guide them in different career possibilities.

Jane: I agree. A mentor will also help them craft their Plan of Study.

Rory: Peers are more important for me. Joining groups will help graduate student enhance their learning experience.

To Restate or Clarify a Formal Statement

If you feel like you need to explain or restate something in another independent clause, a colon is your best friend. An independent clause, for reference, is a clause that stands as a single sentence.

Remember to capitalize the first letter of both independent clauses as if they are separate sentences.

Example:

  • The company only wanted to say one thing: Refunds take 30 days of processing and validation.  
  • There are three variants of bodily muscles: smooth, cardiac, and skeletal.

Before Appositives

In the English language, appositives are nouns or noun phrases that give information about the earlier noun. Use a colon at a sentence’s ending to emphasize an appositive.

Examples:

  • The principal thinks the school should have one priority: the welfare of students.  
  • My wife packs my everyday lunch: a grilled chicken sandwich, Reese’s, and an apple. 
  • This house is how I imagined my childhood dream home: porch swing, good lighting, and arched doorways.

Introduces a Question

Use a colon at a statement’s ending to introduce a question.

Examples:

  • But the frequent question many people ask is this: How much budget should be allotted for scientific research?
  • The question remains: What are the social ramifications of conservative values?
  • This study aims to solve a single question: Should high school students be required to volunteer?
  • The professor asked two questions for the assignment: What does proper grammar mean, and what are the rules of grammar?

Take a look at the above examples, especially the last sentence. The statement after the colon explains the “two questions” in the previous statement. 

It has its own subject and verb. That means it can stand alone as a sentence despite the question variety. Therefore, the word after the colon starts with a big letter.

Introduces a List

One of the most common colon functions is that it can introduce lists or tabular material. It comes before the numbered or bulleted list of items. Take a look at the example of a formal list below.

There are many types of letters:

  • Formal business letter.
  • Letter of application.
  • Letter of excuse.
  • Less-formal letters.

Here’s an example of a numbered list that uses a colon.

The five most common punctuation marks are:

  1. Period.
  2. Question mark.
  3. Comma.
  4. Comma. 
  5. Colon. 

If you want to use a sentence instead of a list, separate the items with commas.

Introduces Quotations

Colons introduce quotations after an independent clause. Do not use a colon for a quote after a dependent clause. Instead, use a comma. 

But if the introduction is a dependent clause and the quotation is at least one sentence, you may use both colon, or comma. 

Whatever rule you follow, do not forget the quotation marks. And observe capitalization after colons if the quotation is a complete sentence. Use a lowercase letter if it’s only one word or a sentence fragment. 

Examples:

  • Incorrect: The assistant said: “You have a difficult job, Ariel.”
  • Correct: The assistant told me a secret: “I think you have a nice style.”
  • Incorrect: According to Leila: “Everyone should be given more time during tests for student success.”
  • Correct: Leila made a great point: “Everyone should be given more time during tests for student success.”

The punctuation mark is also useful for starting extended quotations.​ This type of quotation does not use quotations marks but an indention from the left margin. Below is an example.

The theater actor mentioned his favorite quotation from Shakespeare:

  • If music be the food of love, play on,
  • Give me excess of it; that surfeiting,
  • The appetite may sicken and so die.

Separates Independent Clauses

Use a colon between an introductory clause and another clause or phrase that emphasizes the thought. 

You should also begin the clause with a capital letter if the clause after the colon is a complete sentence or proper noun.

But it can also be a matter of style. In British English, the style is still lowercase if the following explanatory statement is a complete sentence. Merriam-Webster’s style also follows lowercase.

Example:

  • Jessica Alba has two daughters: Honor Marie and Haven Garner.
  • The participants have agreed on the outcome: send out consent forms.
  • The respondents made the next step: They signed the project logs.  
  • I have two tasks for today: read more grammar articles to know the laws of grammar and fix my desk.

Bibliography Entries in Different Citation Styles

Many style guides use a colon to put different pieces of information apart in the bibliography. 

Example:

  • Le Guin, Ursula K., 1929-2018. The Left Hand of Darkness. New York: Ace Science Fiction Books, 19871969.
  • Rowling, J.K. (1999) Harry Potter and the Sorcerer’s Stone. New York: Scholastic.

Colons in Titles, Units of Time, and More

You’ll also find lots of colons in titles. Among the many types of punctuation marks, colons are the most common on headings. If you’re a fan of franchise movies or TV series, you’ve probably seen colons in them. 

Examples:

  • Captain America: Civil War.
  • Star Wars: Episode IV

The subheadings of a writing piece also use colons to introduce them.

Examples:

  • Module 3: Cross-sectional Studies
  • Prisons are Purposeless: An Argumentative Essay on Why Prisons don’t Work.
  • English Perfection: A Grammar Resource.

One of the most common rules of colon usage is the representation of time. These forms of punctuation are found in Bible verses and ratios too.

Examples:

  • The perfect times to visit me are 5:00 PM and 7:30 PM.
  • I’m currently reading Genesis 3:2.
  • Our ratio of teachers to students is 1:5

Common Colon Mistakes

Aside from knowing when to use a colon, it’s also helpful to know when to avoid it. Here are some types of sentences that show punctuation mistakes.

Separating Basic Sentence Parts

A colon should not divide the noun and verb, verb and object or subject complement, and subject from predicate.

Examples:

  • Incorrect: The places I want to visit are: Tokyo, Bali, and the Maldives.

This colon in the sentence unnecessarily separates the subject from the subject complement. There are two methods to correct it.

First, you can create a list.

The places I want to visit are:

  • Tokyo.
  • Bali.
  • The Maldives.

You can also remove the colon, as in “The places I want to visit are Tokyo, Bali, and the Maldives.”

It’s also wrong to separate the preposition and its object with a colon.

Example:

  • Incorrect: This drink is made of: orange juice, dry red wine, apple, and brown sugar.
  • Correct: This drink is made of orange juice, dry red wine, apple, and brown sugar.

To Show Sentence Introductions Through Phrases

You cannot use a colon for your introductory phrase. It’s also not suitable for marking bonus phrases in a sentence. These rules are only for dashes.

Example:

  • Incorrect: Notebook, laptop, reading material, pens: Many students bring these tools to school.
  • Correct: Notebook, laptop, reading material, pen–many students bring these tools to school.

The first sentence implies notebooks, laptops, and pens, saying, “Many students bring these tools to schools.”

Separating Unnecessary Parts of a Sentence

Colons do not separate unnecessary parts of a sentence. It is the parentheses’ job to consider the enclosed material as unnecessary.

Example:

  • The man finally visited his favorite country: Switzerland.
  • The man finally visited his favorite country (Switzerland).

Use the colon as material for emphasis on “Switzerland.” Meanwhile, use parentheses to place less focus on “Switzerland.” 

Using a Colon After a Sentence Fragment

The absolute rule is that only an independent sentence can precede a colon. You should never use colons after sentence fragments.

Example:

  • That Wendy enjoys ice cream flavors: cookie dough, vanilla, chocolate.
  • She enjoys movies like: Easy A, Emma, and Mamma Mia. 

After “Such as,” “Including,” “Especially,” and More

The material before the colon should be a complete statement. But this colon usage violates that rule. Here’s an example:

  • The company is making scientific leaps, such as: exploring renewable energy and producing eco-friendly vehicles.

The previous sentence is wrong because you can omit the phrase “such as.” The correct sentence should be “The company is making scientific leaps: exploring renewable energy and producing eco-friendly vehicles.”

Examples:

  • Incorrect: This cake is made of organic ingredients, including: carrots, goat cheese, and organic multigrain flour.
  • Correct: This cake is made of organic ingredients: carrots, goat cheese, and organic multigrain flour.
  • Incorrect: I am amazed by the event details, especially: the colorful peonies, silverware, and the birthday cake.
  • Correct: I am surprised by the event details: the bright peonies, silverware, and the birthday cake.

Examples of Colon in a Sentence

Here are some examples of how different publications use colons in their sentences.

Our updates include:

  • the Sustainable Farming Incentive in 2022
  • Landscape Recovery and Local Nature Recovery
  • the Lump Sum Exit scheme (UK Government).

Climate change and violence can also be interrelated factors: in Honduras, for example, where repeated droughts linked to climate change have increased food insecurity, widespread violence prevents families from moving elsewhere in the country safely. (Human Rights Watch)

The movie is based on “Being Mortal: Medicine and What Matters in the End,” a 2014 non-fiction book about end-of-life care written by surgeon Atul Gawande. (USA Today).

He said: “Over the last 15 years, I’ve seen her mobility stripped; seen the day she stopped walking independently; the day she started living in a wheelchair; the day she moved into residential care. (BBC)

Among the trends that excite Papilion:

  • the growing integration of climate change into investor strategies and financial regulation,
  • WSP’s continuing evolution into a top advisory and consulting firm for sustainability and climate change mitigation and risk management, and

greater incorporation of resiliency and conservation into large public- and private-sector projects. (CSR Wire)

Use the Colon Properly

Unlike the period or comma, you won’t always find the colon in most sentences. That’s why some people are unaware of this punctuation mark’s functions. I hope this post has shown you the colon basics, including its usage and how to use it in a sentence.

Before using the colon, ask yourself, can the group of words preceding the colon stand on its own? If it can, then pat yourself on the back for using the punctuation mark correctly!

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