The shortest of the dashes, hyphens (–) link words and parts of words. They can connect prefixes or break up a word at the end of a line of text. They can also combine two or more words that describe a noun. For example, in George Orwell’s 1984, hyphenated words help create unusual descriptive phrases: “He felt deeply drawn to him, and not solely because he was intrigued by the contrast between O’Brien’s urbane manner and his prize–fighter’s physique.”
One easy way to tell if you should use a hyphen is to pair each describing word on its own with the noun it’s describing. If the words don’t make sense without each other, you should hyphenate them. In the above example from 1984, the result would be prize physique and fighter’s physique. If the story took place in a modeling contest, prize physique might make sense, but this one doesn’t, so we need a hyphen to add clarity.
Age and numbers
When you write out a number in words, you should use hyphens to show a link between the number words (e.g. “There are ninety–nine people invited.”). You should also use hyphens when writing out someone’s age, as in “I have a 13–year–old son.”
Creating compound verbs
You can use a hyphen to join two nouns, making a compound verb. Some examples of hyphenated compound verbs include ice-skate, window-shop, and air-condition.
Creating compound adjectives
Joining a noun with an adjective, a noun with a participle, or an adjective with a participle creates a compound adjective. A participle is a word formed from a verb and used as an adjective (e.g. “burned toast”) or used as a noun (e.g. “good breeding“).
Some examples of hyphenated compound adjectives are sugar-free, custom-built, and good-looking.
These days, most prefixes aren’t hyphenated, but it’s important to do when the meaning of a word is uncertain. For instance, when a hyphen is used in re-cover, the word means “to put a cover something again.” This helps avoid confusion with recover, which means “to get well.”
Hyphens are especially useful if the prefix ends in a vowel and the word being modified starts with a vowel. Some examples of this include co-own and co-opt.
Hyphens showing word breaks
When the end of a line comes in the middle of a word, you can use a hyphen to divide it in a way it normally wouldn’t be. It’s important to place the hyphen at a point in the word that won’t lead to confusion or misunderstandings. For instance, if the word dislocate needs to be split, the hyphen should come at a syllable break, becoming dis-locate.