Colons

Why is this sentence wrong?

Bilbo Baggins returned to the Shire with: the One Ring and his sword, Sting. 

Answer: The colon is used incorrectly. 

Colons are tricky, but they don't have to be. Unlike a lot of grammar oddities, colons tend to follow more stable rules. How exciting! 

What's the Golden Rule of colons?

A colon always follows a complete sentence. If you're winding up to your colon debut with a sentence fragment, then halt! You shall not pass a colon without a complete sentence first. (Sorry, I couldn't resist.)

Example: Bilbo Baggins returned to the Shire with two key things: the One Ring and his sword, Sting.

The sentence "Bilbo Baggins returned to the Shire with two key things" is complete. It can stand alone. 

So, what does the colon do?

I like to think of colons as the theater curtain. Colons introduce an idea or definition, and they do so with a bit of drama. 

Unlike the semicolon, which acts like a super-comma holding two complete sentences together for deeper meaning, the colon brings the reader to a short stop, shouts, "TA DA!" and reveals something to directly clarify the main sentence.

If all we read was Bilbo Baggins returned to the Shire with two key things, we could easily ask, "Well, what did he bring?" The colon leaps in, stage left, to explain: He returned with the One Ring, and his sword, Sting.  

Using a colon draws keen attention to Bilbo's possession of the One Ring and Sting. This signals to a reader that these elements are especially important, and should be remembered. 

Example: Bilbo passed down the One Ring and Sting to his nephew, Frodo: It was a good call.

What's another use for a colon?

They can introduce vertical lists. The Golden Rule of Colons still applies: Colons always follow a complete sentence.

 Hobbits eat seven meals a day: 

• ​Breakfast
• Second Breakfast
• Elevenses
• Luncheon, and so on.

Are you supposed to capitalize after a colon?

If this question has bugged you since the beginning, then you've noticed that I've both capitalized and not capitalized after the colon. It all comes down to style. 

Strict grammarians will argue that you should always capitalize. 

In ​Lord of the Rings, Rohan represents two elements of Anglo-Saxon social structure: The community space of the Feasting Hall, and the ideal heroic relationship between a liege lord and his thanes.  

I prefer to capitalize only when the segment following the colon is also a complete sentence. If this section is a list or just a partial idea, then I don't capitalize.

(Two Complete Sentences) Bilbo passed down the One Ring and Sting to his nephew, Frodo: It was a good call.

(List or Partial Idea) Bilbo Baggins returned to the Shire with two key things: the One Ring and his sword, Sting.​