A dash breaks the rhythm or interrupts the meaning of a sentence, setting off information with greater emphasis than another punctuation mark could supply. Writers often use dashes to substitute for other punctuation in quick notes and letters to friends. In many kinds of published writing, dashes are used sparingly — but often to good effect.

P5-a Type, space, and position a dash correctly.

Type a dash ( — ) as two hyphens (--) in a row with no spaces before or after. (Your word processing program likely provides the option of converting two hyphens into a dash.) Use one dash before a word or words set off at the end of the sentence. Use two dashes — one at the beginning and one at the end — if the word or words are in the middle of the sentence.

Use a pair of dashes, not just one, to mark the beginning and end of a word group that needs emphasis.

P5-b Consider using a dash to set off material from the rest of the sentence.

Because the dash marks a strong break, it alerts the reader to the importance of the material that follows it.

Use a dash or a pair of dashes to emphasize a definition, a dramatic statement, a personal comment, or an explanation.

Consider inserting a dash or a pair of dashes to emphasize a list.

If the list appears in the middle of the sentence, use one dash at the beginning and another at the end to signal exactly where the list begins and ends.

P5-c Rewrite a sentence that uses the dash inappropriately or excessively.

Use dashes purposefully; avoid relying on them instead of using other punctuation marks or developing clear sentences and transitions.

If you are not sure whether you have used a dash or a pair of dashes appropriately, try removing the material that is set off. If the sentence does not make logical and grammatical sense, one or both of the dashes are misused or misplaced.