Learn how to properly use hyphens with compound adjectives, and more.
Hyphens Can Change Meaning
Sometimes, the placement of a hyphen changes the meaning of your sentence. Let’s say you want a “hot-water bottle.” With a hyphen between “hot” and “water” you clearly want a water bottle for holding hot water because “hot” and “water” are joined by a hyphen. Without the hyphen between “hot” and “water," you might want a water bottle that is hot. See how the presence or absence of a hyphen could change the meaning?
The reason I didn’t say that I absolutely should have hyphenated “noise canceling headphones” is that if leaving out the hyphen causes no ambiguity, some style guides, such as the Chicago Manual of Style, say it’s OK to leave it out; and I don’t think anyone would read my meaning differently with or without a hyphen.
In the “hot water bottle” example, the difference is pretty subtle too. You probably don’t need the hyphen, but it’s not wrong to use it either because someone probably could be confused.
The more likelihood there is for confusion, the more you need a hyphen.
The Grammar Monkeys account on Twitter, run by the editors of The Wichita Eagle, often tweets examples of sentences they see where a missing hyphen makes a big and funny difference. Many of these are things they actually saw in news stories. Two of their recent “Why we need a hyphen” examples were as follows:
Why we need hyphens: Because a small-state senator is not the same as a small state senator. — Grammar Monkeys (@GrammarMonkeys) November 15, 2012
Why we need hyphens: Because a violent weather conference isn't the same as a violent-weather conference — Grammar Monkeys (@GrammarMonkeys) October 5, 2012
Prefixes and Hyphens
Some prefixes need hyphens, such as “re—,” “mid—,“ and “ex—.“ For example:
My ex-boyfriend took the movies I enjoyed.
The mid-1990s were interesting.
Santa needed to re-read the Naughty or Nice list.