Hyphens and Dashes

What's the difference between a hyphen and a dash? How do you know when to use one or the other of these punctuation marks?

A hyphen is a short, single-character line which connects word parts.
The hyphen serves two primary functions:
  1. to divide words that split at the end of a line
  2. to join word parts into a single word.

A dash is a longer line—double the length of a hyphen—which indicates a break or an interruption in the thought.
Dashes are used to set off part of a sentence. Unlike parentheses, which tend to minimize, dashes tend to emphasize the set-off text.

Using these punctuation marks correctly will help you make your meaning clear to your readers. In the next few screens, we'll look at each of these marks individually to see how they are used.