After publication of last month’s column on uses of the em-dash, a reader emailed to ask why the instructions I shared for creating this punctuation mark call for leaving no space on either side of it.

He asked the question like so: “You made a point I have sometimes wondered about—that there should be no space before or after an em-dash.”

While the em-dash in the sentence above mirrors its appearance in most publications, in some, including The New York Times (as he noted), it looks like it does in this version of his sentence: “You made a point I have sometimes wondered about – that there should be no space before or after an em-dash.”

While I agreed that the latter is more pleasing to the eye, I explained that putting spaces before and after an em-dash makes the mark more difficult to distinguish from an en-dash.  Indeed, some writers would say that the mark in the second version of his sentence is, in fact, an en-dash, and not an em-dash at all.  But technically, they would be incorrect, because an en-dash should never have a space on either side.  So, some punctuation experts say that using a “space-en-dash-space” in lieu of a proper em-dash is the “wrong-n method” for emphasizing a clause that is independent of the main sentence, but it is an acceptable one nonetheless.  (For example, we used the “wrong-n” or “wrong-en” method to make the em-dashes in last month’s column as it appears on the Legal by the Bay blog.)

All this raises a question: What is an en-dash, and when should we use that punctuation mark?

The en-dash is wider than a hyphen and narrower than an em-dash.  It stands in for the word through or the words up to and including.  In Microsoft Word, you can create one by pulling down the menu on the “insert” tab, selecting “advanced symbol” and “normal font” or “normal text,” and then clicking on the mid-sized dash available in the grid.

So named because its width is that of a typesetter’s N (just as an em-dash’s is that of a typesetter’s M), the en-dash is used to join numbers in a range, as in A.D. 1066–1215, or to tie words together that mark a span of time, such as Monday–Friday.  In a Q and A from The Chicago Manual of Style Online, the en-dash is described as a connector of “things related to each other by distance, as in the May–September issue of a magazine.”  “It’s not a May-September issue,” the unidentified writer explains, “because June, July, and August are also ostensibly included in this range.”

By the same logic, you would use an en-dash to mark a span of pages in a citation: (Cheong at pp. 548–550).  Or to describe an airborne trip across the Atlantic: “British Airways Flight 238 Boston­–London takes six and a half hours.”  An en-dash can also be used to show the score in a sports game: “The Braves beat the Cubs 9–4.”

Be careful not to “mix words and the en-dash,” as legal writing expert Bryan Garner advises in LawProse Lesson #185 on his www.lawprose.org website.  If you introduce a range of numbers or any other things with the word from, use the word to instead of an en-dash.  Likewise, if you introduce the range with the word between, use the word and.

Thus, we write, “Edgar Allan Poe lived from 1809 to 1849,” not “Edgar Allan Poe lived from 1809–1849.”  And we write, “Top hats were at their tallest between 1800 and 1850,” not “Top hats were at their tallest between 1800–1850.”

Garner also says we should use an en-dash instead of a hyphen “to join or pair elements of equal weight,” e.g. “Taft–Hartley Act,” “attorney–client privilege,” and “respected writer–editor.”

Lastly, you can use an en-dash to connect a prefix or a single noun to a proper, open, compound noun (meaning a proper, compound noun that cannot be hyphenated), such as “the post–Civil War period” or “San Francisco Giants–related memorabilia.”  In these examples, it’s appropriate to use a dash than can do a little more work than an ordinary hyphen.

About the author:

Savannah Blackwell is a former news reporter who covered government and politics in San Francisco for more than a decade and is now Of Counsel at Renne Public Law Group.  She can be reached at savannah.blackwell@gmail.com.  Follow her on Twitter at @SavannahBinSF.