Writing for Business and Pleasure
First published March 28, 2003
To paraphrase Mark Twain, the difference
between a dash and a hyphen is like the difference between lightning and a
lightning bug. Yet many writers confuse the two punctuation marks.
The mighty dash (–) is charged with energy. It produces a sudden jolt of emphasis, an abrupt pause that draws a dramatic halt to the rhythm and flow of a sentence.
The lowly hyphen (-) is a nondescript mark. Intended for the eye rather than the ear, it functions without personality, style, or rhythmic impact.
The confusion might result from the dash never having been given its rightful place on the keyboard. When the typewriter was invented in the 19th century, the dash was omitted, perhaps because it could be replicated by typing two hyphens, like this: --.
Most word-processing programs make up for this omission by automatically joining two separate hyphens into a solid dash. Some software programs also elongate a hyphen into a dash when a space appears before and after the hyphen.
There are actually two types of dashes: em dashes and en dashes. As their names imply, em dashes and en dashes were at one time the length of the letters m and n. This distinction provided a handy way for letterpress operators like Benjamin Franklin to know if he had picked up the right dash and, after a page was printed, to return it to its appropriate box in his type case.
En dashes, which are shorter than em dashes and longer than hyphens, are used to mark intervals, as in continuing times ("The meeting is scheduled for 8-9 a.m.") and in continuing dates ("The years 1994-99 were a period of great economic prosperity").
But now that you know about en dashes, forget about them. (Whew!) They are used almost exclusively in published materials. When using word processors, you and I use hyphens in place of en dashes.
So our concern is using hyphens correctly and using em dashes – generally referred to simply as dashes – to good effect. Here’s how:
Use hyphens both to divide and to connect. More specifically, use hyphens between the components of#Divided words, as in im-pov-er-ish #Compound names, as in Richards-Wilbers #Compound nouns, as in shrink-wrap #Compound verbs, as in spot-check #Compound adjectives – also called "unit modifiers" – when they precede the word modified, as in up-to-date information (but This information is up to date) #Intervals (in word-processed text), as in 2000-03.
Use dashes to indicate a sudden break in thought or sentence structure. More specifically, use dashes to#Set off an interruption, as when William Strunk and E. B. White wrote, "His first thought on getting out of bed – if he had any thought at all – was to get back in again." #Set off a mid-sentence phrase that contains a series of items separated by commas, as in "Attending to the five elements of effective writing – purpose, organization, support, expression, and correctness – will make you a better writer." #Mark the end of a long summary, as when Joyce Carol Oates wrote, "Our intelligence, our wit, our cleverness, our unique personalities – all are simultaneously ‘our own’ possessions and the world’s." #Mark the beginning of a long summary, as in "She has many qualities – qualities such as integrity, candor, commitment, and genuine concern for others." #Mark an author’s name after a quotation, as in "‘Have dash. Will travel.’ – Anonymous."