Grammar: Compound Word

Posted January 11, 2015 by Kathy Davie in Author Resources, Editing, Grammar Explanations, Self-Editing, Writing

Revised as of 27 June 2017

Compound words are a wide-ranging mishmash of rules covering words, numbers, proper nouns, adjectives, adverbs, directions, titles, and more. There’s also a hodgepodge of positioning and implication.

Writers will have to think as well, lol. I know, I know, more thinking on top of thinking…eek. The rules change depending on if it’s a Wednesday…well, not really. It only seems that way *more laughter*.

Getting serious, whether a compound of words is closed, open, temporary, permanent or other, if you question it, look it up in a dictionary. Use whichever dictionary you are already using as you write or edit.

In general, Chicago Manual of Style says to leave it as an open compound if the dictionary doesn’t tell you to use hyphens or to close it up. Of course, that general rule doesn’t apply when it comes to adjectival or temporary compound words!

Grammar Explanations is…

…an evolving list of the structural rules and principles that determines where words are placed in phrases or sentences as well as how the language is spoken. Sometimes I run across an example that helps explain better or another “also known as”. Heck, there’s always a better way to explain it, so if it makes quicker and/or better sense, I would appreciate suggestions and comments from anyone… Are there areas of grammar with which you struggle? If you’d like to track it, bookmark this page and consider sharing this Grammar Explanation with friends by tweeting it.

Compound Word
Credit to: Chicago Manual of Style, 6.78, 7.83, 7.84, 7.85; Grammarly Handbook: Hyphen With Compound Modifiers
Definition: Compound words may be adjectives, adverbs, or nouns and how they are treated will change with which part of grammar they are and their location within a sentence.

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Rules for:


Also see:

Closed Compound Rule: Spelled as a single word. The current trend is toward closed with CMOS using on line as an example of how it has progressed from on-line to online.

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birthrate
citywide
online
notebook
stepdaughter
grandmother
stepgrandson
worldwide
Rule: Compass points and directions are closed IF only two directions are combined.

CAUTION: If three directions are combined, a hyphen must be used after the first direction.

northeast
southeast
northwest
southwest
north-northeast
east-southeast
west-northwest
CAUTION: If a from…to is implied, use an en dash.
Phrase The Implied From…To
The street runs east–west. The street runs from east to west.
It’s a north–south race. The race runs from north to south.
Hyphenated Compound Rule: Spelled with one or more hyphens with the intention of making the phrasing more readable and understandable and with two or more words.

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full-time
kilowatt-hour
mass-produced
non-English-speaking
non-achievement-oriented
part-time
Not Hyphenating Compound Words
Leads to Confusion
Compound Word The Implication
fast decision making make a snap judgement
fast decision-making make a decision soon
much needed clothing They’ve got a lot of clothing.
much-needed clothing This clothing is so essential.
an abbreviation: pre-UCS trial
Open Compound Rule: Spelled as two or more words OR using a comparative or superlative adjective that creates a short phrase with a focused meaning.

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Two or More Words Using a Comparative/Superlative
high school better built house
lowest common denominator more likely outcome
Revolutionary War best laid plans
Rule: Chemical terms do not use hyphens.
Sodium hydroxide
Permanent Compounds Rule: One that has been accepted into the general vocabulary and is found in a dictionary. It’s fairly safe to say that anytime a single letter is attached to a word, it’s with a hyphen.

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f-stop
T-shirt
browbeat
e-mail
pre-K
copyeditor
under-the-counter
highlight
waterfall
anti-inflammatory
matter-of-fact
over-the-counter
pre-engineered
Temporary Compounds Rule: A new combination created for some specific, often one-time purpose. CMOS notes that these may eventually be accepted as permanent, but are not normally found in a dictionary.
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impeachment hound (I like this one!)
Compound Modifier Definition: Hyphenate when two or more words in front of a noun act as one idea. Linking them together clarifies which word is playing which role.

A.k.a., Phrasal adjective, one-thought adjective

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Consider What the Reader Will Understand
Two Words How It Affects the Sentence
The American made car. Sounds like someone doesn’t speak English very well.
The American-made car. Instantly explains that this car is made in America.
It’s recommended you not take down any load bearing walls when renovating. Oops, make sure that load over there isn’t holding up a wall.
It’s recommended you not take down any load-bearing walls when renovating. Ohhh, you mean I shouldn’t take down any walls that are holding up a load.
This is a low budget job. So, this is a budget job, and it’s low on the list of jobs to be done?
This is a low-budget job. Ah, it’s a job we’re doing as cheaply as possible.
First class decisions require clear headed thinking. First, any decisions we may for the class must be clear decisions. They must also be headed thinking. (I’m not sure what “headed” means.)
First-class decisions require clear-headed thinking. Making the best decisions mean we need to be thinking clearly about them.
He has a devil may care attitude. He has an attitude that the devil is going to be concerned about. (Ain’t that scary!)
He has a devil-may-care attitude. He has a cheerful attitude.
Position Within a Sentence is a Changer
CAUTION: When using a compound modifier, pay attention to its position within the sentence. If it comes before the word being modified, use the hyphens. If it comes after the word being modified, do NOT hyphenate.

Before the Modified Word After the Modified Word
He is a well-respected man. That man is well respected.
It’s a well-written story. That story is well written.
This is a government-mandated program. This program is government mandated.
I love that blue-green dress. That dress is a lovely blue green.
Get the reddish-brown stone. You want the stone that is reddish brown?
He’s a second-rate baseman. As a baseman, he’s second rate.
Wow, we’re in a first-row seat! Wow, we’re sitting in the first row!
It’s all-out war. She went all out to impress him.
Exceptions to the position rule
Always Hyphenate Examples
ex-
(noun that expresses a former state)
Her ex-husband got fired.

Tell him we hire ex-cons.

She’s his ex-wife.

self- It’s self-evident that she cheated.

The instructions say it’s self-acting.

Rule: Modifiers that end in -ly are never hyphenated.
YES NO
That was a badly punctuated sentence. That was a badly-punctuated sentence.
It was a fully developed plan. It was a fully-developed plan.
She’s a a nationally recognized teacher. She’s a a nationally-recognized teacher.
We sent in heavily fortified troops. We sent in heavily-fortified troops.
Rule: Proper nouns and proper adjectives are never hyphenated as they are already correct.
YES NO
The South American rain forest is home to hundreds of species of hummingbirds. The South-American rain forest is home to hundreds of species of hummingbirds.
Rule: When numbers or units of measure are used as an adjective, hyphenate them.
two-seater aircraft thirty-pound weakling
4-bedroom house five- to ten-minute intervals
nineteenth-century painter 12-inch rule
pre-1998 three-week course
Exceptions to the “hyphenate numbers” rule.
Percent Always spell percent out in text
Never use %
Never hyphenate
a 15 percent raise
Compounds with Prefixes Rule: While there are some exceptions, compounds created by the addition of a prefix are not hyphenated. No, this is not a complete list of prefixes.

Prefixes with a dotted underline are also combined forms.

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ante- antecedent
anteroom
antechamber
mid- midsection
midtown
midway
anti- antimanagement
antismoking
antisocial
mini- minibike
minicab
minicomputer
bi- binomial
bimonthly
biannual
mis- misinformed
mismanage
misprint
bio- biochemistry
biography
multi- multicultural
multiplex
co- coordinate
copayment
coworker
neo- neonate
neoromantic
neoimpressionists
counter- counterbalance
counterclockwise
counterpoint
non- nonaffiliated
nonaggression
nonviolent
de- decompress
deduct
descend
out- outfight
outmoded
outpost
dis- disbar
dislike
disgruntled
over- overanxious
overemphasize
overplay
extra- extraordinary
extracurricular
extraterritorial
post- postoperative
posttraumatic
postwar
hyper hyperactive
hyperlink
hyperthyroid
pre- precaution
precede
prejudge
in- inanimate
inpatient
intolerant
pseudo- pseudointellectual
psuedonym
pseudoscience
infra- infrastructure re- reactivate
revert
reunify
inter- interactive
interagency
interrelated
semi- semicircular
semiconductor
semidarkness
intra- intramural
intrauterine
socio- socioeconomic
sociolinguistics
macro- macroeconomics
macroevolution
macronutrient
sub- subalpine
submarine
subpar
mega- megabyte
megahertz
megalith
super- superman
superstructure
supertanker
meta- metacarpus
metamorphosis
metaphysical
trans- transatlantic
transcontinental
translate
micro- microcircuit
microdot
microeconomics
un- uninfected
unnatural
under- undercover
underdeveloped
undernourished
Exceptions include:
Rule: Use a hyphen if the second element is capitalized or a number
anti-Semitic
post-Freudian
pre-Civil War
Rule: If a hyphen is needed to avoid confusion between words that would conflict.
co-op a cooperative society
coop a building for chickens
re-form cause to form again
reform make changes in something to improve it
re-pair pair up again
repair fix
un-ionized not ionized
unionized become members of a union
Rule: Use a hyphen if a vowel or consonant would be repeated so as to avoid confusion.
anti-intellectual antiintellectual
semi-independent semiindependent
ball-like balllike

Exceptions to this rule include:
reestablish
reedit

Rule: Use a hyphen if the compound word would be difficult to read without a hyphen.
pro-life prolife
pro-choice prochoice
co-edited coedited
Suspended Compound Definition: Rather than repeat the same final term in a list, the completion of the compound words is deferred until the last item in the list while allowing the hyphen to act as a placeholder.

A.k.a., combined noun compounds

second-, third-, and fourth-grade teachers

full- and part-time employees

1-, 2-, and 3-year-old children

under- and overdeveloped nations get together

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