Colons – How to Use them Correctly

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Colons-Definition

The colon is the most forward-thinking punctuation mark in English, but it’s also the most misused and challenging: you’re never sure when to use it. This post explains what a colon is, frequently asked questions (FAQs) about the punctuation mark, the uses and rules for a colon, and how they differ from semicolons.

Colons – In a Nutshell

The rules for using colons are straightforward, and you shouldn’t interchange them with a comma, period, or semicolon.1 Using this punctuation mark makes your writing more effective. This is because a colon:

  • Declares
  • Announces
  • Introduces

Definition: Colons

Colons (:) are punctuation marks that introduce phrases, elaborations, words, quotations, and explanations. Often, independent clauses precede a colon: an independent clause is a sentence that makes sense on its own.2

What are the rules for using colons?

There are plenty of rules surrounding the use of punctuation marks in English. Here are some of the rules to keep in mind when using a colon:

Bullet lists

Colons precede bullet lists, for instance:

Some mental health disorders include:

  • Depression
  • Anxiety
  • Insomnia
  • Schizophrenia
Colons bullet lists

Introducing extended quotations

Introduce extended quotations with a colon (avoid quotation marks) and single space the indent and quote from the left margin.

Example:

Dyer’s philosophy stipulates that thoughts manifest reality:

Act as though your thoughts and desires are already a reality. Remove any thoughts of its limitations, conditions, and possibilities not manifesting.

Separating a full sentence quote looks like this (remember to start the quote in CAPS):

Joyce announced to the team: “I intend to quit.”

Formal letters

The salutations of formal or personal letters use a colon. Follow the name of the person you’re writing to with a colon.

Example:

Dear Mr. Griffin:

Dear Professor Jackson:

The uses of Colons

A colon has three grammatical uses with several non-grammatical uses, as explained below:

Grammatical uses of the colon

The grammatical uses of a colon are:

Introducing a list

When introducing a list, use the colon if the items aren’t incorporated into the sentence’s flow.

Take this sentence as an example:

The book store sells three genres: horror, romance, and thriller.

Correct

The book store sells horror, romance, and thriller genres.

Incorrect

The book store sells: horror, romance, and thriller genres.

Between independent clauses

Use a colon to separate two independent clauses when the second sentence amplifies the first one.

Example:

My new job starts in a month: I have little time left to learn the guitar.

When two or more sentences come after the colon, capitalize the first word of the first sentence.

Example:

She made three observations: First, they were losing millions yearly. Second, the rate of employee turnover was low. Third, managers and immediate employees didn’t get well together.

Emphasis

A colon also emphasizes a single word or phrase at the end of a sentence.

Example:

The jury reached the uncontended verdict after a month: guilty.

Four continents, two dozen countries, unimaginable cities: this was the vacation of his lifetime.

Non-grammatical uses of the colon

Non-grammatical use of a colon involves:

Time: A colon separates hours and minutes. For example, 2:54 p.m.
Ratio: A colon expresses ratios of two numbers. For example, the percentage of 4:5.
Biblical references: A colon separates biblical verses and chapters, e.g., Psalms 103:14
Correspondence: A colon is effective in personal and business correspondence e.g.:

- Dear Mr. Bromfield
- CC: Jane Doe
- Attention: Payroll Payment
Other references: A colon separates a volume of pages and cited work, e.g., Punctuation Quarterly 6:108-150 (volume 6 reading from page 108 to 150)

Colons vs. semicolons

Both colons and semicolons are used between two independent clauses or grammatical sentences.3Semicolons only show that the two sentences are related; a colon shows the second sentence amplifies the first.

Example:

Semicolon: Jane is afraid of windows; as a child, she thought an alien world existed beyond them.

Colon: Jane is afraid of windows: as a child, she thought an alien world existed beyond them.

FAQs

No. You should only use a colon with two complete sentences.

No. A colon amplifies two sentences, while a semicolon shows that two sentences have a relation.

You should avoid using colons before a verb and number and after a preposition.

Sources

1 PurdueUniversity. “Identifying Independent and Dependent Clauses.” Accessed September, 19, 2022. https://owl.purdue.edu/owl/general_writing/punctuation/independent_and_dependent_clauses/index.html.

2 The Writer’s Handbook. “Using Semicolons.” Accessed on September 19, 2022. https://writing.wisc.edu/handbook/grammarpunct/semicolons/.

3 EnglishGrammar. “The Full Stop and Comma.” June 19, 2010. https://www.englishgrammar.org/full-stop-comma/.