Everyone knows that hyphens are used at the end of a line of type to indicate that a word continues on the next line.
Beyond that use of hyphens, some people run into confusion.
Some get downright grumpy when it comes to using hyphens in phrasal adjectives.
The journalist Lynne Truss, author of Eats, Shoots & Leaves, a humorous book about punctuation, explains that the hyphen joins words to aid understanding. Her chapter on hyphens defends the honor of sober pickled-herring merchants who have never touched a drop.
Without a hyphen, the phrase “long term plan” might leave a reader wondering whether there is something called a term plan, and he’s reading about a long one. With a hyphen, the phrase “long-term plan” lets the reader be sure he is reading about a plan for the long term.
The rule is this: If two consecutive words work together as an adjective to modify a noun that follows them, those two words should be hyphenated.
The rule is not just for two words; it is the same when any number of words work together as a modifier before a noun:
an easy-to-reach shelf
the head-over-heels-in-love couple
No hyphen is necessary if the noun does not follow the modifying words:
the up-to-date report
the report is up to date
An exception to the hyphen rule applies when the first word in the compound adjective ends in –ly. In that case, the meaning is clear without a hyphen. For example:
an openly hostile environment
a clearly attainable goal
Hyphens have other uses, too. We’ll save those for another day.