Dashes (– or —)

Dashes are used often as a matter of emphasis or to signal a change in tone, and the grammatical rules for their use are loose—they can be used in some of the same places as commas, colons, semicolons, and parentheses.

Beginning writers often confuse dashes with hyphens, probably the most common dash-related mistake.

Dash as a hyphen

Examples

“Some years ago-never mind how long precisely-I thought I would sail about a little and see the watery part of the world.”

“Some years ago — never mind how long precisely — I thought I would sail about a little and see the watery part of the world.”

“Some years ago – never mind how long precisely – I thought I would sail about a little and see the watery part of the world.”

“Some years ago—never mind how long precisely—I thought I would sail about a little and see the watery part of the world.”

Note the difference between the size of the dashes in the last two examples. The shorter is an “en dash” while the longer is an “em dash.”

Most copy editors will advise use of the em dash, except in very particular circumstances, but in practice many writers use these two interchangeably. If you choose to use the “en dash” to punctuate your sentence structure, use it consistently and avoid the “em dash.”

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2 comments

Lou Benders
June 15, 2015 at 5:25 PM

Dear Dorothy,

Writing guidelines on when to use a hyphen is definitely a good idea!

In your case carbon-based is indeed correct. This is a compound adjective, just like well-known, good-looking, bad-tempered, carbon-neutral and custom-built.

Most compound adjectives are hyphenated and some are not. Sometimes hyphens are used in such adjectives to avoid that the meaning becomes ambiguous. This is the case with '100 year old men', which could be referring to 100 men that are a year old, or to men that are 100 years old.

However, whether you should use a hyphen or not, is not always clear. Thus, this is some food for thought!

We will definitely think about writing an article on the subject!

Reply

dorothy de kok
June 3, 2015 at 5:54 PM

How about some guidelines on when to use a hyphen and when not? e.g. is it carbon-based material or carbon based material? I go with the first one, but there is nothing here to support my opinion.
Really love your articles!

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