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When do You Hyphenate Compound Words?

Jessica Ellis
Jessica Ellis
Jessica Ellis
Jessica Ellis

Hyphens are a notoriously tricky punctuation mark. English is a fairly inconsistent language and the student is not helped by the constant trend of evolution of the rules. To ensure absolute correctness when using hyphens, keep a good dictionary nearby, for knowing when to hyphenate compound words is not a definite science.

Compound words are two or more individual words that have a different or enhanced meaning when combined. For instance, “bumble” can mean to drop or fumble something, “bee” can be either an insect or a gathering, but a “bumblebee” is a distinct word used for a specific flying insect. Compound words are either written as one word, two words, or two words connected by a hyphen. Therein lies the complications, as no one seems able to properly define when to hyphenate compound words at all.

Terms such as "merry-go-round" are always written with a hyphen.
Terms such as "merry-go-round" are always written with a hyphen.

A common rule in determining whether a compound word should be one word or two is how the word is used in context. Phrases that have a verb/noun or verb/adjective combination should be two words if the combined term is a verb and one word if the compound word is a noun or description. For instance, “my car will never break down” uses “break” as a verb, whereas “Michael had a breakdown” uses “break” as part of a noun. This is useful in determining the difference between one and two word compound phrases, but does not really help us with whether to hyphenate compound words or not.

Terms such as "mother-in-law" are always written with a hyphen.
Terms such as "mother-in-law" are always written with a hyphen.

One usually consistently hyphenated form of compound words are those with a connecting middle word. Terms such as merry-go-round or mother-in-law are almost always written with a hyphen. One exception is commander in chief, which is frequently seen without the hyphen, especially when referring to the President of the United States as an alternate title.

A dictionary can help ensure the correct use of hyphenated words.
A dictionary can help ensure the correct use of hyphenated words.

Knowing the linguistic origin of may help determine when to hyphenate compound words. Many compound words with a Germanic root are written as one word, such as fisherman. Still, as with all hyphenating words, this is not entirely consistent, and having at hand knowledge of the early origin of most words is a skill not many possess.

The best guideline to remember when dealing with common words is that extremely common terms, like someday, always, and highway, are rarely hyphenated. If you are using a new or unusual compound, check in a dictionary to see if the term exists, and if so, how it is punctuated. If you cannot find the word, it is best to hyphenate it, as it is clearly not in common usage.

Don’t panic when worrying about whether to hyphenate compound words. The rules are so uncertain that it is rare to be docked grammatical points on essays or tests for incorrect hyphenation. If you are accused of misusing or neglecting the hyphen, go to your professor or the person who graded your work and politely ask them to show you some proof that your usage is incorrect. Chances are, they will be guessing, too!

Jessica Ellis
Jessica Ellis

With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica is passionate about drama and film. She has many other interests, and enjoys learning and writing about a wide range of topics in her role as a LanguageHumanities writer.

Learn more...
Jessica Ellis
Jessica Ellis

With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica is passionate about drama and film. She has many other interests, and enjoys learning and writing about a wide range of topics in her role as a LanguageHumanities writer.

Learn more...

Discussion Comments

anon195931

Give me some examples of hyphenated compound words.

upnorth31

Did you know that the novel "Moby Dick" was originally hyphenated? In fact, a lot of hyphen use has become obsolete. These words that used to have a hyphen are now just one word, or two separate words.

roxytalks

I'm always confused when it comes to knowing when to hyphenate a word. It will help me in the future to know these rules, even if they are not always consistent -- most rules in the English language aren't. Next time I find myself using a hyphen in the word mother-in-law, at least I'll know I'm right!

DentalFloss

These days, you can also almost always find what you are looking for in terms of hyphen rules in an online dictionary if you don't have one in book form on hand.

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    • Terms such as "merry-go-round" are always written with a hyphen.
      By: EvanTravels
      Terms such as "merry-go-round" are always written with a hyphen.
    • Terms such as "mother-in-law" are always written with a hyphen.
      By: Monkey Business
      Terms such as "mother-in-law" are always written with a hyphen.
    • A dictionary can help ensure the correct use of hyphenated words.
      By: Maciej Zatonski
      A dictionary can help ensure the correct use of hyphenated words.