Guide to Using Hyphens in Compound Words

Recently I’ve gotten a little obsessed with compounds words and the hyphen, that little punctuation mark that can cause so much confusion. My interest in this started when I was looking into the spelling of the word “healthcare.” Oops! I mean “health care”… or “health-care”?

The spelling of this word gives people have a hard time. Merriam-Webster’s dictionary gives the spelling “health care” for the noun and explains that the spelling “health-care” is usually used attributively.

Ex. I need better health care, so I’m looking at my health-care options.

The Chicago Manual of Style agrees with this. APA suggests “health care” for both the noun and the adjective, relying on one of its general rules for hyphens: don’t use a hyphen unless it serves a real purpose. The AP also uses “health care” (but not “health-care”), and if you Google “healthcare” you will find it is used all over the place by reputable organizations, including many hospitals, and by everyone in the English-speaking world outside of North America.

Considering this mish-mash, I figured Proofreading Pulse’s readers could use some information on such compound words, which are words made up of more than one word or of a base word and a prefix of suffix. Compound words can be open (written as two separate words), hyphenated (the parts are connected with a hyphen), or closed (the parts are written without spaces or hyphens). Here are some examples:

• Open compound: hot air (noun, as in, “That’s a bunch of hot air.”)
• Hyphenated compound: hot-air (adjective, as in, “Oh no! The hot-air balloon is sinking!”)
• Closed compound: hothead (noun, as in, “What a hothead!”)

Here are some examples of compounds with prefixes, but only hyphenated and closed compounds because compounds with prefixes don’t come in an open variety:

• Hyphenated: bi-level, co-operative, re-read
• Closed: bilateral, omnipresent, uneven

So how’s a writer supposed to know how to spell a compound word? There are, thankfully, a few general rules:

• Most style guides recommend avoiding unnecessary hyphens. So unless there’s a possibility of confusion if you don’t use a hyphen, leave the hyphen out.
• Compounds made of two words often form open compounds when used as nouns but may form hyphenated compounds when used as adjectives.

Ex. “It’s in the living room.” (no hyphen)
Ex. “It’s on the living-room rug.” (hyphen)

• Compounds made from more than two words almost always form hyphenated compounds.

Ex. “He wears a hard-to-fit size shoe.”

• Drop the hyphen in a hyphenated compound if it comes after what it is modifying.

Ex. “This is a time-consuming project.” (hyphenated compound)
Ex. “This project is time consuming.” (no hyphen)

• Compounds made of a base word and a prefix or suffix generally form closed compounds.

Ex. antibacterial, precalculus, microanalysis

• Compounds made of two words often start out as open or hyphenated compounds but over time and with use may become closed compounds. The words “bookstore” and “policeman” were once open. Perhaps in a few years we will be saying the same thing about “health care.”

As I said, there are quite a few exceptions to these rules. I’ll go into detailed rules and exceptions in an upcoming blog. For now, when dealing with a compound word you’re not sure about, first check the dictionary, then if you’re still not sure follow the guidelines listed above, and most important, make sure to be consistent with how you treat compound words throughout your writing. If you hyphenate it once, do it all the time.

Sarah P.