The Hyphen-Dash family is a group of punctuation marks that is made up of the Hyphen, the en Dash, and the em Dash. Each is a horizontal line of varying length that appears centered vertically in a typed or written line.
The hyphen is a friendly punctuation mark: it likes to bring words a little closer together to emphasize their compound nature. It is the shortest of the Hyphen-Dash family, but it still manages to hold quite a few things together. Here are some quick rules for using hyphens.
Hyphenate a compound modifier appearing before the noun:
Hyphenate modifying phrases appearing before a noun:
glass-half-full outlook on life
Hyphenate prefixes such as (pro-, anti-, neo-, mid-, post-, pre-):
mid-century / pro-trampoline / anti-beard / post-modernism etc.
Hyphenate written fractions and compound numbers between twenty-one and ninety-nine:
two-thirds of a cup of sugar / nine-tenths of the law / seventy-six
Do not hyphenate a compound modifier following a noun:
The classroom is student-centered. X
The classroom is student centered.
Do not hyphenate a compound modifier when its first word ends in –ly (usually an adverb):
They went to the rapidly-freezing lake. X
They went to the rapidly freezing lake.
Though they may look similar, dashes and hyphens have opposite functions: dashes interrupt or interject a sentence while hyphens connect words that act as a single idea.
Dashes allow the writer to strongly emphasize the parenthetical material by dramatically drawing attention to it. It shines a spotlight on a group of words, signaling to the reader that those words are not a part of the main clause and should be given some additional attention. Dashes also allow the writer to show range, create tension, and emphasize various parts of compound modifiers.
The en Dash is the next largest dash--slightly larger than the hyphen--as it is the same width as the letter N. In order to type this middle-child dash, type a hyphen between the words you intend to connect and put a space before and after it. Most word processors will automatically lengthen the hyphen into the en Dash.
The en Dash shows limits in a range of values (such as numbers, dates, pages, times, cost):
Numbers: 156 – 294
Dates: June 6th – June 8th
Page numbers: pages 11 – 15
Time: 10:36 am – 12:47 pm
Cost: $4,000 – 5,000
The em dash--the width of the letter M--is a visual cue to the reader that what appears either after the dash or between two dashes is parenthetical information, a side comment represented on the page:
Could you please—oh, forget it!
The em dash is twice as long as a hyphen; in fact, when you are typing an em dash, simply type two hyphens—no spaces between the words before or after the dash(es), and no spaces between the two hyphens—and most word processors will automatically unite the two hyphens into an em dash.
Do not use an em dash to connect two main or independent clauses. An em dash can only hold together a main clause and a subordinate or dependent clause.
Don’t touch the—I guess the stove isn’t hot anymore, so it’s not a big deal.
I didn’t think Stew’s would be this messy—I guess I don’t really know how messy I thought his house would be. X