Create emphasis and define terms by interrupting the flow of a sentence by using a dash; know when the dash must be used as opposed to the comma.

Some stylists view the dash with great suspicion--the sort of suspicion that a man in the 1990s who wears a plaid leisure suit to work would arouse. Some people erroneously believe that the dash is acceptable only in informal discourse.

However, the dash can provide you with subtle ways to repeat modifiers and dramatic ways to emphasize your point.

Create emphasis and define terms by interrupting the flow of a sentence by using a dash; know when the dash must be used as opposed to the comma.

Some stylists view the dash with great suspicion--the sort of suspicion that a man in the 1990s who wears a plaid leisure suit to work would arouse. Some people erroneously believe that the dash is acceptable only in informal discourse. However, the dash can provide you with subtle ways to repeat modifiers and dramatic ways to emphasize your point.

Use a Dash after a Series or List of Appositives

When you introduce a long series or list of appositives before the subject and verb, you are placing high demands on the reader's short-term memory. Therefore, use this pattern rarely and only for emphasis. This pattern is particularly appropriate in conclusions, when you are bringing together the major threads of your discussion or argument. Finally, you should place a summary word after the dash and preferably before the subject of the sentence, as indicated by the following examples. The most common summary words that writers use are all, those, this, each, what, none, such, these.

  • Jealousy, lust, hate, greed--these are the raw emotions we will explore.
  • Lying, stealing, cheating, committing adultery--which is the greatest sin?
  • To struggle with meaning, to edit, to combine sentences--these activities are well known to the struggling writer.
  • Wining and dining his friends, stroking people's egos, maintaining a good appearance, and spending money--all were part of his scheme to gain influence.

Use Dashes When You Wish to Emphasize a Parenthetical Element

Commas are usually sufficient punctuation to set off parenthetical elements. In some instances, however, you can use a dash instead, especially if you want to make the insertion more noticeable:

  • The building next to ours--the one with the all-cedar exterior--was engulfed in flames.

When you want to whisper rather than shout, you can place the modifiers inside parentheses:

  • The secret I have to tell you (the one I've been hinting about) will surprise you.

Use Dashes to Embed a Series or List of Appositives

A single appositive or modifier can easily be set off from the rest of the sentence in commas, but you must use dashes when you insert a series of appositives or modifiers. After all, how else will the reader know when the series is over?

  • The essential qualities of an effective writer--discipline, effort, inspiration--can be learned by regular writing.
  • With the help of her assistant--a high-speed personal computer--she produced a delightful letter.

Use Dashes to Set off an Emphatic Repetition

You can emphasize an important point by placing a dash or comma at the end of the sentence and then repeating a key word or phrase:

  • Hal is a computer, the ultimate computer.
  • Mrs. Leavitt is a gambler, a compulsive gambler.
  • He was disturbed by the warning--the warning that everyone else ignored.
  • All rapists should be severely punished--punished in a way they will never forget.