A hyphen is used:
To join compound words: mother-in-law, teen-age.
To join words used as single adjective before a noun: It was a well-paved highway.
No hyphen is used:
a. When the compound adjective follows the noun: The highway was well paved.
b. When the first word is an adverb ending in -ly: The neatly cut lawn was much admired.
- With compound numbers from 21 to 99 and with fractions: twenty-two, fifty-first, three-fourths.
Note: Some authorities write fractions without the hyphen: three fourths.
A compound adjective containing numbers is also hyphenated: a ten-year old boy, a forty-hour week, the hundred-yard dash, a ten-dollar bill, a *two-room *apartment, two- and three-story houses.
To avoid ambiguity:
One sense: She recovered her pillow from the dog.
Other sense: She covered her pillow in red silk.
Misleading: Along came *fifty foot *soldiers.
Clear: Along came fifty foot-soldiers.
With prefixes ex, self, all, and the suffix elect: ex-President Hoover, self-confidence, all American, Senator-elect Smith.
a. Bi and tri are not hyphenated prefixes: triweekly, bimonthly.
b. Semi is hyphenated only (1) when combined with words beginning with* i* (semi-independence); or with proper noun (semi-Russian); otherwise, it is not hyphenated (semiannual, semiprofessional, etc.).
To indicate hesitation or stutterings: “I’m g-g-glad,” she said.
To indicate words that spelled out: “She wants a d-o-l-l,” her mother said.
For syllabication (a division between syllables at the end of a line): . . . The classroom can a accommodate thirty pupils.
Note: The hyphen is placed at the end of the first line, at the beginning of the second line. Consult a dictionary if you are uncertain where a word is divided.
Aren’t you sorry you asked? :mrgreen: