Hyphens


Hyphens Between Words

Rule 1

To check whether a compound noun is two words, one word, or hyphenated, you may need to look it up in the dictionary. If you can't find the word in the dictionary, treat the noun as separate words.

Examples:
eyewitness, eye shadow, eye-opener

NOTE:
All these words had to be looked up in the dictionary to know what to do with them!

Rule 2

Phrases that have verb, noun, and adjective forms should appear as separate words when used as verbs and as one word when used as nouns or adjectives.

Examples:
The engine will eventually break down. (verb)
We suffered a breakdown in communications. (noun)
Please clean up your room. (verb)
That Superfund site will require specialized cleanup procedures. (adjective)

Rule 3

Compound verbs are either hyphenated or appear as one word. If you do not find the verb in the dictionary, hyphenate it.

Examples:
To air-condition the house will be costly.
We were notified that management will downsize the organization next year.

Rule 4

Generally, hyphenate between two or more adjectives when they come before a noun and act as a single idea.

Examples:
friendly-looking man
(compound adjective in front of a noun)
friendly little girl
(not a compound adjective)
brightly lit room
(Brightly is an adverb describing lit, not an adjective.)

Rule 5

When adverbs not ending in -ly are used as compound words in front of a noun, hyphenate. When the combination of words is used after the noun, do not hyphenate.

Examples:
The well-known actress accepted her award.
Well is an adverb followed by another descriptive word. They combine to form one idea in front of the noun.

The actress who accepted her award was well known.
Well known follows the noun it describes, so no hyphen is used.

A long-anticipated decision was finally made.
He got a much-needed haircut yesterday.
His haircut was much needed.

Rule 6

Remember to use a comma, not a hyphen, between two adjectives when you could have used and between them.

Examples:
I have important, classified documents.
Jennifer received a lovely, fragrant bouquet on Valentine's Day.

Rule 7

Hyphenate all compound numbers from twenty-one through ninety-nine.

Examples:
The teacher had thirty-two children in her classroom.
Only twenty-one of the children were bilingual.

Rule 8

Hyphenate all spelled-out fractions.

Examples:
You need one-third of a cup of sugar for that recipe.

More than one-half of the student body voted for removing soda machines from campus.

Hyphens with Prefixes

Rule 1

The current trend is to do away with unnecessary hyphens. Therefore, attach most prefixes and suffixes onto root words without a hyphen.

Examples:
noncompliance
copayment
semiconscious
fortyish

Rule 2:

Hyphenate prefixes when they come before proper nouns.

Example:
un-American

Rule 3

Hyphenate prefixes ending in an a or i only when the root word begins with the same letter.

Examples:
ultra-ambitious
semi-invalid

Rule 4

When a prefix ends in one vowel and a root word begins with a different vowel, generally attach them without a hyphen.

Examples:
antiaircraft

proactive

Rule 5

Prefixes and root words that result in double e's and double o's are usually combined to form one word.

Examples:
preemployment
coordinate

Exceptions:
de-emphasize
co-owner

Rule 6

Hyphenate all words beginning with self except for selfish and selfless.

Examples:
self-assured
self-respect
self-addressed

Rule 7

Use a hyphen with the prefix ex.

Example:
His ex-wife sued for nonsupport.

Rule 8

Use the hyphen with the prefix re only when:

the re means again AND omitting the hyphen would cause confusion with another word.

Examples:
Will she recover from her illness?
Re does not mean again.

I have re-covered the sofa twice.
Re does mean again AND omitting the hyphen would have caused confusion with another word.

The stamps have been reissued.
Re means again but would not cause confusion with another word.

I must re-press the shirt.
Re means again AND omitting the hyphen would have caused confusion with another word.

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