The Hyphen ( - )

A hyphen is  a mark (-) . A dash is a mark (--) . A dash is longer than a hyphen.  Hyphenation is used for joining words together.  Another difference between a dash and a hyphen is that hyphens are also used for dividing syllables of words.

There are so many rules that govern the use of hyphens in English:

1.     Put a hyphen between two words that function as a single adjective when the modifier comes before the words it modifies.  

The once-popular resort area had become a ghost town.

The ill-fated mission in high causalities.

Note : The hyphen is unnecessary if the first word in the compound ends in ly or if the noun precedes the modifier:

The previously injured players returned to action before the end of the season.  

The resort area that was once popular had become a ghost town.

2.     Put a hyphen or ( a slash ) between two nouns to combine them into a single noun.

The player- coach took herself out of the game.


If the compound is formed by the combination of a noun and one or more different parts, consult a dictionary for recommended usage. In one recently published dictionary , words such as break-in, editor-in chief , and ice skating are hyphenated , but similar types of compounds are printed as two separate words (e.g. boundary line , ice water , etc ) or as a single unhyphenated word (e.g., bricklayer )  

3.     Use a hyphen to form a compound of two numbers that are written as words:
Twenty-five people have already preregistered for organic chemistry.

The nineteen-sixties will be remembered as a decade of discontent.

4.     Use a hyphen after a prefix when the root word is a proper noun or adjective or when the omission of the hyphen would result in an awkward repetition of letters or confusion of meaning.
Anti- American sentiment {  the hyphen links the prefix with a proper noun , America }



I want to re- lease ( i.e., renew the lease on ) this apartment next year.  { Without a hyphen , release would convey the opposite meaning: give up }

5.     When you do not have enough space to complete a word of two or more syllables at the end of a line, divide the word after a syllable and insert a hyphen to indicate that word will be completed on the next line:
If you are in doubt about where to divide a word , consult a dictionary.

ar.chi.tect / bi.ol.o.gist / frac.ture



Reference:


Kirkland, James . W  & Dilworth , Collett. B  Concise English Handbook Houghton Mifflin Company 1983