Hyphen

A hyphen is a punctuation mark. It is used both to join words and to separate syllables. It is often confused with a dash, which is longer. Hyphenation is the use of hyphens.

• Nouns formed of two nouns, or a noun and an adjective, are frequently hyphenated, as death-wish.

• In general, when a compound modifier appears before a term, and at least one of the elements is itself a modifier, the compound modifier is hyphenated in order to prevent any possible misunderstanding, such as light-blue paint, twentieth-century invention, cold-hearted person, and award-winning show. Without the hyphens, there is potential confusion about whether "light" applies to "blue" or "paint", whether "twentieth" applies to "century" or "invention", etc. However, hyphens are generally not used if both elements of the compound modifier are nouns, such as government standards organization, and department store manager, nor if the first element is an adverb ending in "-ly", such as truly remarkable progress.

• Names for numbers from twenty-one to ninety-nine often have hyphens, as shown in this sentence.

• Hyphens are also used to denote syllabification, as in syl-lab-i-fi-ca-tion.

• If a word is split onto two lines, a hyphen will usually be inserted immediately before the split.

• Some married women non-traditionally compose their last name by appending their husband's last name to their maiden name using a hyphen.

Due often to ignorance or apathy, and sometimes to being unconvinced of its utility, the hyphen has ceased to be used by many—perhaps most—educated people, including those who publish in scholarly journals. Its use is almost always avoided by those who write advertising copy or labels on packaging, since they are often more concerned with visual cleanliness than semantic clarity. However, it is still used in most newspapers and magazines, so people remain accustomed to seeing and understanding it. Most writers who are obstreperous about other things are compliant when editors tell them to hyphenate compounds. Anyone who doubts that the hyphen is marvelously efficient as an information-conveying device may consider the obvious difference in meaning between two newspaper headlines:

New age-discrimination rules proposed

New-age discrimination rules proposed

or:

The disease causing poor nutrition was identified.

(which means the disease that causes poor nutrition...) versus:

The disease-causing poor nutrition was identified.

(which means the disease that is caused by poor nutrition).

Additional examples of proper use:

text-only

a Detroit-based organization

web-based

a state-of-the-art product

board-certified

thought-provoking

time-sensitive

case-sensitive

government-issued photo ID

light-gathering surface

award-winning

a fun-loving person

a man-eating shark (Without a hyphen, this would mean a customer in a seafood restaurant.)

how to wire-transfer funds

how to tax-plan

an advertising-supported service

Rudolph Giuliani is an Italian-American

list of China-related topics

Out-of-body experience

Near-death experience

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In computer programming, the hyphen corresponds to Unicode and ASCII character 45, or 0x002D.