In English, words, particularly adjectives and nouns, are combined
into compound structures in a variety of ways. And once they are formed,
they sometimes metamorphose over time. A common pattern is that two
words — fire fly, say — will be joined by a hyphen for a time — fire-fly
— and then be joined into one word — firefly. In this respect, a
language like German, in which words are happily and immediately linked
one to the other, might seem to have an advantage. There is only one
sure way to know how to spell compounds in English: use an authoritative dictionary.
- There are three forms of compound words:
- the closed form, in which the words are melded together,
such as firefly, secondhand, softball, childlike, crosstown, redhead,
keyboard, makeup, notebook;
- the hyphenated form, such as daughter-in-law, master-at-arms, over-the-counter, six-pack, six-year-old, mass-produced;
- and the open form, such as post office, real estate, middle class, full moon, half sister, attorney general.
How a word modified by an adjective — "a little school," "the yellow butter" — is different from a compound word — " a high school," "the peanut butter"
— is a nice and philosophical question. It clearly has something to do
with the degree to which the preceding word changes the essential
character of the noun, the degree to which the modifier and the noun are
inseparable. If you were diagramming a sentence with a compound word, you would probably keep the words together, on the same horizontal line.
Modifying compounds are often hyphenated to avoid confusion. The New York Public Library's Writer's Guide
points out that an old-furniture salesman clearly deals in old
furniture, but an old furniture salesman would be an old man. We
probably would not have the same ambiguity, however, about a used car
dealer. When compounded modifiers precede a noun, they are often
hyphenated: part-time teacher, fifty-yard-wide field, fire-resistant
curtains, high-speed chase. When those same modifying words come after
the noun, however, they are not hyphenated: a field fifty yards wide,
curtains that are fire resistant, etc. The second-rate opera company
gave a performance that was first rate.
Comparative and superlative forms of adjectives are hyphenated when
compounded with other modifiers: the highest-priced car, the
shorter-term loan. But this is not always the case: the most talented
youngster. Adverbs, words ending in -ly, are not hyphenated when
compounded with other modifiers: a highly rated bank, a partially
refunded ticket, publicly held securities.
Sometimes hyphenated modifiers lose their hyphens when they become
compound nouns: A clear decision-making process was evident in their
decision making. The bluish grey was slowly disappearing from the
bluish-grey sky. This is not always so, however: your high-rise
apartment building is also known as a high-rise.
When modifying a person with his or her age, the compounded phrase is
hyphenated: my six-year-old son. However, when the age comes after the
person, we don't use a hyphen. My son is six years old. He is, however, a
Most dictionaries will give variant spellings of
compound plurals. When you have more than one truck filled with sand, do
you have several truckfuls or trucksful? The dictionary will give you
both, with the first spelling usually preferred. (And the same is true
of teaspoonfuls, cupfuls, etc.) The dictionary will help you discover
that only one spelling is acceptable for some compounds — like passersby.
For hyphenated forms, the pluralizing -s is usually attached to the element that is actually being pluralized: daughters-in-law, half-moons, mayors-elect. The Chicago Manual of Style
says that "hyphenated and open compounds are regularly made plural by
the addition of the plural inflection to the element that is subject to
the change in number" and gives as examples "fathers-in-law,"
"sergeants-in-arms," "doctors of philosophy," "and courts-martial"
(196). The NYPL Writer's Guide puts it this way: "the most
significant word — generally the noun — takes the plural form. The
significant word may be at the beginning, middle, or end of the term"
(396). And then we get examples such as "attorneys at law," "bills of
fare," chiefs of staff," notaries public," assistant attorneys general,"
"higher-ups," "also-rans," and "go-betweens."
Note: some dictionaries will list "attorney
generals" along with "attorneys general" as acceptable plurals of that
office. Whether that's a matter of caving in to popular usage or an
inability to determine the "significant word" is unknown.
As a general rule, then, the plural form of an
element in a hierarchical term belongs to the base element in the term,
regardless of the base element's placement:
The possessive of a hyphenated compound is created
by attaching an apostrophe -s to the end of the compound itself: my
daughter-in-law's car, a friend of mine's car. To create the possessive
of pluralized and compounded forms, a writer is wise to avoid the apostrophe -s
form and use an "of" phrase (the "post genitive") instead: the meeting
of the daughters-in-law, the schedule of half-moons. Otherwise, the
possessive form becomes downright weird: the daughters-in-law's meeting,
friends of mine's cars.
One of the most difficult decisions to make about
possessives and plurals of compound words occurs when you can't decide
whether the first noun in a compound structure is acting as a noun that
ought to be showing possession or as what is called an attributive noun,
essentially an adjective. In other words, do we write that I am going
to a writers conference or to a writers' conference? The Chicago Style Manual suggests that if singular nouns can act as attributive nouns — city government, tax
relief — then plural nouns should be able to act as attributive nouns:
consumers group, teachers union. This principle is not universally
endorsed, however, and writers must remember to be consistent within a
This section does not speak to the matter of
compounded nouns such as "Professor Villa's and Professor Darling's
classes have been filled." See the section on Possessives for additional help.
Compounds with Prefixes
With a handful of exceptions, compounds created by the addition of a prefix are not hyphenated:
anteroom, antisocial, binomial, biochemistry, coordinate,
counterclockwise, extraordinary, infrastructure, interrelated,
intramural, macroeconomics, metaphysical, microeconomics, midtown,
minibike, multicultural, neoromantic, nonviolent, overanxious, postwar,
preconference, pseudointellectual, reunify, semiconductor,
socioeconomic, subpar, supertanker, transatlantic, unnatural,
- Exceptions include
compounds in which the second element is capitalized or a number:
- anti-Semitic, pre-1998, post-Freudian
- compounds which need hyphens to avoid confusion
- un-ionized (as distinguished from unionized), co-op
- compounds in which a vowel would be repeated (especially to avoid confusion)
- co-op, semi-independent, anti-intellectual (but reestablish, reedit)
- compounds consisting of more than one word
- non-English-speaking, pre-Civil War
- compounds that would be difficult to read without a hyphen
- pro-life, pro-choice, co-edited
Also, when we combine compound nouns, we would use a
hyphen with the first, but not the last: when under- and overdeveloped
nations get together. . . .
The following table presents a mini-dictionary of compound modifiers
and nouns. Perhaps the best use of a very partial inventory like this
is to suggest the kinds of words that a writer would be wise either to
memorize or to be at least wary of. It is sometimes enough to know when
we should get the dictionary off the shelf.
Notice that African American contains no hyphen, but Italian-American
does. There are no hard and fast rules about this, and social
conventions change. (There is no hyphen in French Canadian.) Some
groups have insisted that they do not want to be known as "hyphenated
Americans" and resist, therefore, the use of a hyphen, preferring that
the word "American" be used as an adjective. Some resources even suggest
that a term like Italian-American should be used only when the
individual thus referred to has parents of two different nationalities.
That's probably a stretch, but a writer must be aware that sensibilities
can be aroused when using nationalities of any description. Consistency
within a document is also important.
With a series of nearly identical compounds, we
sometimes delay the final term of the final term until the last
instance, allowing the hyphen to act as a kind of place holder, as in
Be careful not to overuse this
feature of the hyphen; readers have to wait until that final instance to
know what you're talking about, and that can be annoying.