There's a punctuation mark that most people have never heard of or noticed, even though they've probably seen it in print 1,000 times.

It's called the en dash, or N dash. And it's a great example of how weird the wild world of punctuation can be.

Case in point: I can't show you one. En dashes, though common in book and magazine publishing, are almost nonexistent in news media. Associated Press editing style doesn't acknowledge that they exist. Historically, most news organizations didn't have the ability to transmit an en dash over a newswire or print one on a page. So most news organizations never got in the habit of using en dashes.

In the news world, the word "dash" refers to an em dash, which is twice as long as a hyphen. If you type two hyphens into a word-processing program, there's a good chance your computer will turn the hyphens into an em dash for you.

Em dashes signify a break in sentence flow. They can set off lists — long lists, short lists, you name it. They can set off parenthetical information — just as parentheses do — that you don't want to put in parentheses. And em dashes can show a switch in grammatical structure, like — well, you know.

Book editing uses no spaces around its em dashes, but news editing usually opts for a space on either side.

Hyphens, which are half as long as dashes, are used in certain compound nouns (drive-in), verbs (water-ski), and adjectives, including adjectives that already exist (good-looking) and ones you assemble yourself (nutrient-rich). Hyphens also connect some prefixes and suffixes to words, but only when the hyphen is necessary to aid comprehension (re-create, anti-incremental) or to attach the prefix or suffix to a proper noun (pro-America).

In most news media, as well as in most academic and scientific journals, that's it. There's a hyphen and an em dash, but there is no en dash.

The little en dash exists almost exclusively in book publishing and the magazines that follow book publishing style. Readers don't usually notice them, which makes sense when you consider that they exist solely to make written text smoother and easier to digest.

The en dash is longer than a hyphen but shorter than an em dash. It has a few specific jobs, mostly working in places where a hyphen might leave things looking a little tight but where an em dash would appear too long.

Mainly, the en dash is used for ranges, where it does the job of a word like "to," "through" or "until." These can include years, hours, dates, ages and sports scores: "The 2001-02 school year brought some curriculum changes." "Happy hour: 3-7." "A Miami-Dallas flight." Those would all have en dashes in a published book.

A range that begins with "between" or "from," however, needs its partner word, "and" or "to," and not an en dash. So it's "between 8 and 5," not "between 8-5."

En dashes also do some hyphen-like jobs, especially working with "open compounds" of two or more words. In "pre-World War II," "a George Washington-like figure" and "a Black Dahlia-inspired crime," book style calls for an en dash, which looks better than a hyphen with these terms.

Finally, en dashes also connect things that already have their own hyphens: "a semi-private-semi-public entity" would have an en dash in the middle, making clearer the relationships between all the units.

If you want to see an en dash, it's in a lot of Microsoft Word versions, usually under "Insert," then "symbols," then "more symbols," then "special characters." Or you can just keep your eyes peeled next time you read a book. The en dash is probably in there somewhere.

JUNE CASAGRANDE is author of "It Was the Best of Sentences, It Was the Worst of Sentences." She can be reached at JuneTCN@aol.com.