Punctuation: Semicolons & Colons

Familiarize yourself with how to use both colons ( : ) and semicolons ( ; ) in academic writing.

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Semicolon

The semicolon is the most misused and misunderstood piece of punctuation. Essentially, semicolons exist only to join independent clauses (i.e., complete sentences). Picture it as a period sitting on top of a comma. The period signals that the semicolon must be preceded by an independent clause; the comma indicates that the semicolon intends to link related elements into a single sentence.

In order to use a semicolon, the sentences must not only be short but also have an obvious connection in meaning.

Anna loves figure skating; she hates hockey.

He loves her; she loves him.

Frank burnt himself; he still has the scar.

 1.   Between two complete thoughts before a transition word or phrase

When a conjunctive adverb (e.g., however, nevertheless, therefore, thus) or a transitional phrase (e.g., for instance or in fact) appears between two independent clauses, it must be preceded by a semicolon, and is usually followed by a comma.

Bring your I.D. card; otherwise, you won’t be allowed in.

She does a lot of travelling between semesters; for example, on the last semester break, she went to Mexico.

Princess Leia senses a mystic connection with Luke Skywalker; in fact, she is his sister.

Subordinators (e.g. because, when) and coordinators (e.g. and, or, but, so, for, yet) cannot be used with a semi-colon. However, a semicolon may take the place of one of these joining words.

 2.    Between items in a list

Usually commas are used to separate items in a list. However, sometimes commas are needed within items in a list; in those cases, semicolons are used to separate the listed items.

I am struggling to decide what university to attend: U.B.C., which has a big beautiful campus; S.F.U., which is close to my home; or U.C.F.V., which is smaller and more personal.

Colons

Colons may be followed by a phrase, a list, a quotation, or even another independent clause.

1. Lists

The colon is used to introduce a list after a complete sentence.

We have three levels of government: municipal, provincial and national.

The biscuit recipe calls for these ingredients: flour, butter, baking powder, and milk.

Although the battle at Dieppe was a disaster, it served some useful purposes: it distracted the enemy from the Eastern front, it taught the Allies about the importance of reconnaissance, and it gave the inactive Canadian troops in Britain something to do.

2. Long Quotations

Colons are also used to introduce long quotations.

Bettelheim (1975) explains the importance of fairy tales to children’s development:

Today, as in the past, the minds of both creative and average children can be opened to an appreciation of all the higher things in life by fairy tales, from which they can move easily to enjoying the greatest works of literature and art. (p. 23)

Note: Colons should be used sparingly, especially as a means of introducing single sentence quotations. Rather, try to integrate the quotation into the syntax of your sentence.

3. Connect two sentences if the second is a restatement or further explanation of the first.

 Minds are like parachutes: they only work when they are open.

I devised a new exercise plan: I would get up early and jog every morning.

4. Other Uses of the Colon

The other uses of the colon are very specific.

 i) Colons are used to follow salutations in formal and business letters.

 Dear Dr. Jones:

 ii) Colons are used between the hour and the minutes in time expressions.

 6:45 p.m.

He ran the marathon in 4:27:53.

 iii)  Colons are used between main titles and sub-titles.

 A book I found very useful for writing my paper was Bruno Bettelheim’s The Uses of Enchantment: The Meaning and Importance of Fairy Tales.

Common Errors in Colon Use

1.  A colon should not come after a verb like is or are. This is wrong because a complete sentence is needed before a colon.

 This is wrong:

The causes of Cathy’s success are: her intelligence, her hard-working approach, and her high level of motivation.

Explanation: “The causes of Cathy’s success are” is not a complete sentence.

This is fine:

Cathy is successful for a number of reasons: her intelligence, her hard-working approach, and her high level of motivation.

Explanation: “Cathy is successful for a number of reasons” is a complete sentence.

You may see examples of colons being used after incomplete sentences in novels, newspapers and magazines, but in formal academic writing, you must have a complete sentence before a colon.

2. A colon cannot be used to introduce a list in the middle of a sentence, only at the end of a sentence.

This is wrong:

John bought some groceries: tea, eggs and lettuce, for his mother.

This is fine:

John bought his mother some groceries: tea, eggs and lettuce.

3.  A colon cannot be used to separate complete sentences. A semi-colon (;) is used for that.

This is wrong: He loves her: she loves him.

This is fine: He loves her; she loves him.


Adapted from Douglas College Learning Centre’s handouts on Semicolons and Colons and Queen’s University Writing Centre’s Semicolons and Colons.

Last updated December 17, 2015