An en dash or en rule (–) is wider than a hyphen (-) and narrower than an em dash (–). The en dash is neglected by many writers except as a substitute for an em dash, and even then it is increasingly replaced with a hyphen to mark a pause or parenthesis, especially online and, less commonly, in print journalism. Among British and Australasian publishers, it is preferred to the em dash, although style guides differ.
The en dash has several common uses.
1. En dashes stand in for versus—for example:
the Obama–McCain debate
the Chargers–Broncos game
2. An en dash shows range—for example:
The London–New York flight.
The U.S.–Australia Free Trade AgreementThe Smith–Jones paper
Note that an en dash can alter the meaning markedly. For example, the Spanish-American War (i.e., the war that took place in Spanish America) is different from the Spanish–American War (i.e., the war between Spain and America).
Typing the en dash
In Mac OS X, an en dash can be rendered very simply by holding the option key down and typing a hyphen.
Under Microsoft Word’s default settings, an en dash is automatically rendered by typing one or two spaced hyphens. Alternatively, you can create an en dash by holding down the control key and typing a hyphen on the numeric keypad, if you have one.
Sometimes, especially online, writers will simply substitute a dash with two hyphens with a space on each side.