- Indicates that part of a word of more than one syllable has been carried over from one line to the next:
During the revolution, the nation was be-
set with problems—looting, fighting, and famine.
- Joins the elements of some compounds: great-grandparent, attorney-at-law, ne'er-do-well.
- Joins the elements of compound modifiers preceding nouns: high-school students, a fire-and-brimstone lecture, a two-hour meeting.
- Indicates that two or more compounds share a single base: four- and six-volume sets, eight- and nine-year olds.
- Separates the prefix and root in some combinations; check a dictionary when in doubt about the spelling: anti-Nazi, re-elect, co-author, re-form/reform, re-cover/recover, re-creation/recreation.
- Substitutes for the word to between typewritten inclusive words or figures: pp. 145–155, the Boston–New York air shuttle.
- Punctuates written-out compound numbers from 21 through 99: forty-six years of age, a person who is forty-six, two hundred fifty-nine dollars.
See also: The Dash and the Hyphen.
More on Hyphen from Fact Monster: