Grammar Focus: Colons and Semicolons

Colon

There are several ways to use a colon, but the most important thing to know is that a colon must always follow a complete sentence. Never use a colon after a sentence fragment.

Correct	Incorrect
To bake these cookies, you will need these ingredients: flour, sugar, butter, chocolate chips, baking powder, eggs, and vanilla.	To bake these cookies, you will need: flour, sugar, butter, chocolate chips, baking powder, eggs, and vanilla.
Paraguay and Bolivia share at least one important feature: they are both without a coastline.	The important feature that Paraguay and Bolivia share is: they are both without a coastline.

Follow these additional rules when using colons:

Rule	Text
Use a colon to join two clauses when the second clause emphasizes or illustrates the first.	Upon Trinity Sunday at night King Arthur dreamed a wonderful dream, and that was this: it seemed that he saw upon a platform a chair and the chair was fastened to a wheel; thereupon King Arthur sat in the richest cloth of gold that might be made. Le Morte d’Arthur
Use a colon to introduce a list after an independent clause.	The Britons immediately found themselves under attack from groups they thought of as barbarians: the Irish from the west, the Picts from the north, and the Anglo-Saxons from across the North Sea. Unsolved Mysteries of History: An Eye-Opening Investigation into the Most Baffling Events of All Time
Use a colon to introduce a quotation within a sentence or paragraph. Be sure to capitalize the first word following the colon when introducing a quotation or dialogue.	The Roman historian Tacitus described the fierce loyalty of the Germanic warriors from whom the Anglo-Saxons were descended: “On the field of battle it is a disgrace to a chief to be surpassed in courage by his followers, and to the followers not to equal the courage of their chief. And to leave a battle alive after their chief has fallen means life-long infamy and shame.” British Literature &History: The Anglo-Saxon Period and Middle Ages (449-1485)

Remember to add one space after a colon.

Semicolon
A semicolon does the same thing as a comma and a coordinating conjunction (and, but, or, nor, for, yet, or so) —it joins two independent clauses. Never use a colon with a coordinating conjunction.

Correct	Incorrect
Many people enjoy feeding birds at the backyard feeder in the winter; the sight of the birds is a sign that spring is just around the corner.	Many people enjoy feeding birds at the backyard feeder in the winter; and the sight of the birds is a sign that spring is just around the corner.
Carly has learned that hard work usually pays off; for example, her complex project won the science fair last year.	Carly has learned that hard work usually pays off; and for example, her complex project won the science fair last year.

Follow these additional rules when using semicolons:

Rule	Text
Use a semicolon to join two clauses that are closely connected.	There was never a castle here in the medieval sense; the fortified hill itself was the “castle,” as elsewhere in southern and southwest England. Conversation with Geoffrey Ashe re: King Arthur
Use a semicolon to join two independent clauses with a conjunctive adverb (such as however) or another transition word or phrase (such as for example). A comma may follow the transition word or phrase.	He called on her for clear judgment, for courage, for honor and fidelity; in short, for such virtues as he knew. Woman in the Nineteenth Century
Use a semicolon to separate items in a series when one or more of the items already contains commas.	Well-educated people needed to know three languages, however: French for dealing with the nobility of the courts; Latin for the church, business, and scholarship; and English for communication with the majority of the common people. Literary History: The Development of English