U.S. Government Printing Office Style Manual/Compounding Rules
(See also Chapter 7 "Compounding Examples")
A compound word is a union of two or more words, either with or without a hyphen. It conveys a unit idea that is not as clearly or quickly conveyed by the component words in unconnected succession. The hyphen is a mark of punctuation that not only unites but separates the component words, and thus facilitates understanding, aids readability, and ensures correct pronunciation. When compound words must be divided at the end of a line, such division should be made leaving prefixes and combining forms of more than one syllable intact.
In applying the rules in this chapter and in using the list of examples in the following chapter, "Compounding Examples," the fluid nature of our language should be kept in mind. Word forms constantly undergo modification. Two-word forms, which often acquired the hyphen first, frequently bypass the hyphen stage and instantly assume a one-word form.
The rules, therefore, are somewhat flexible. Exceptions must necessarily be allowed. Current language trends continue to point to closing up certain words which, through either frequent use or widespread dissemination through modern media exposure, have become fixed in the reader's mind as units of thought. The tendency to merge two short words continues to be a natural progression toward better communication.
In general, omit the hyphen when words appear in regular order and the omission causes no ambiguity in sense or sound.
- banking hours
- blood pressure
- book value
- census taker
- day laborer
- eye opener
- fellow citizen
- living costs
- palm oil
- patent right
- real estate
- rock candy
- training ship
- violin teacher
Words are usually combined to express a literal or nonliteral (figurative) unit idea that would not be as clearly expressed in unconnected succession.
- afterglow
- bookkeeping
- cupboard
- forget-me-not
- gentleman
- newsprint
- right-of-way
- whitewash
A derivative of a compound retains the solid or hyphenated form of the original compound unless otherwise indicated.
- coldbloodedness
- footnoting
- ill-advisedly
- outlawry
- praiseworthiness
- railroader
- Y-shaped
A hyphen is used to avoid doubling a vowel or tripling a consonant, except after the short prefixes co, de, pre, pro, and re, which are generally printed solid. (See also rules 6.29 and 6.32.)
- cooperation
- deemphasis
- preexisiting
- anti-inflation
- micro-organism
- semi-independent
- brass-smith
- Inverness-shire
- thimble-eye
- ultra-atomic
- shell-like
- hull-less
- but
- co-occupant
- cross section
Print solid two nouns that form a third when the compound has only one primary accent, especially when the prefixed noun consists of only one syllable or when one of the elements loses its original accent.
- airship
- bathroom
- bookseller
- cupboard
- dressmaker
- fishmonger
- footnote
- locksmith
- workman
Print solid a noun consisting of a short verb and an adverb as its second element, except when the use of the solid form would interfere with comprehension.
- blowout
- breakdown
- hangover
- holdup
- makeready
- markoff
- pickup
- builddown
- cooldown
- runoff
- setup
- showdown
- thowaway
- tradeoff
- flareback
- giveaway
- but
- cut-in
- phase-in
- run-in
- sit-in
Compounds beginning with the following nouns are usually printed solid.
- book
- eye
- horse
- house
- mill
- play
- school
- shop
- way
- wood
- work
Compounds ending in the following are usually printed solid, especially when the prefixed word consists of one syllable.
- berry
- bird
- blossom
- board
- boat
- book
- borne
- bound
- box
- boy
- brained
- bug
- bush
- cam
- craft
- field
- fish
- flower
- fly
- girl
- grower
- headed
- hearted
- holder
- hopper
- house
- keeper
- keeping
- land
- light
- like
- line
- load
- maid
- maker
- making
- man
- master
- mate
- mill
- mistress
- monger
- over
- owner
- but #ownership
- person
- picker
- picking
- piece
- plane
- power
- proof
- roach
- room
- shop
- site
- skin
- smith
- stone
- store
- tail
- tight
- time (not clock)
- ward
- ware
- water
- way
- wear
- weed
- wide
- wise
- woman
- wood
- work
- worker
- working
- worm
- worthy
- writer
Print solid any, every, no, and some when combined with body, thing, and where. When one is the second element, print as two words if meaning a single or particular person or thing. To avoid mispronunciation, print no one as two words at all times.
- anybody
- anything
- anywhere
- anyone
- everybody
- everything
- everywhere
- everyone
- nobody
- nothing
- nowhere
- no one
- somebody
- something
- somewhere
- someone
but any one of us may stay; every one of the pilots is responsible; every body was accounted for
Print compound personal pronouns as one word.
- herself
- himself
- itself
- myself
- oneself
- ourselves
- themselves
- thyself
- yourself
- yourselves
Print as one word compass directions consisting of two points, but use a hyphen after the first point when three points are combined.
- northeast
- southwest
- north-northeast
- south-southwest
also north-south alignment
- agreed-upon standards
- Federal-State-local cooperation
- Baltimore-Washington road
- German-English descent
- collective-bargaining talks
- guided-missile program
- contested-election case
- hearing-impaired class
- contract-bar rule
- high-speed line
- cost-of-living increase
- large-scale project
- drought-stricken area
- law-abiding citizen
- English-speaking nation
- long-term loan
- fire-tested material
- line-item veto
- long-term-payment loan
- low-cost housing
- lump-sum payment
- most-favored-nation clause
- multiple-purpose uses
- no-par-value stock
- one-on-one situation
- part-time personnel
- rust-resistant covering
- service-connected disability
- state-of-the-art technology
- supply-side economics
- tool-and-die maker
- up-or-down vote
- U.S.-owned property; U.S.-flagship
- 1-inch diameter; 2-inch-diameter pipe
- a 4-percent increase, the 10-percent rise
- but
- 4 percent citric acid
- 4 percent interest. (Note the absence of an article: a, an, or the. The word of is understood here.)
Where meaning is clear and readability is not aided, it is not necessary to use a hyphen to form a temporary or made compound. Restraint should be exercised in forming unnecessary combinations of words used in normal sequence.
- atomic energy power
- bituminous coal industry
- child welfare plan
- civil rights case
- civil service examination
- durable goods industry
- flood control study
- free enterprise system
- ground water levels
- high school student
- elementary school grade
- income tax form
- interstate commerce law
- land bank loan
- land use program
- life insurance company
- mutual security funds
- national defense appropriation
- natural gas company
- per capita expenditure
- Portland cement plant
- production credit loan
- public at large
- public utility plant
- real estate tax
- small businessman
- Social Security pension
- soil conservation measures
- special delivery mail
- parcel post delivery
- speech correction class
but no-hyphen rule (readability aided); not no hyphen rule
Print without a hyphen a compound predicate adjective or predicate noun the second element of which is a present participle.
- The duties were price fixing.
- The shale was oil bearing.
- The effects were far reaching.
- The area is used for beet raising.
Print without a hyphen a compound predicate adjective the second element of which is a past participle. Omit the hyphen in a predicate modifier of comparative or superlative degree.
- The area is drought stricken.
- This material is fire tested.
- The paper is fine grained.
- The cars are higher priced.
- Moderately fine grained wood.
- The reporters are better informed.
Print without a hyphen a two -word modifier the first element of which is a comparative or superlative.
- better drained soil
- best liked books
- higher level decision
- highest priced apartment
- larger sized dress
- better paying job
- lower income group
- but
- uppercrust society
- lowercase, uppercase type
- upperclassman
- bestseller (noun)
- lighter-than-air craft
- higher-than-market price
Do not use a hyphen in a two-word unit modifier the first element of which is an adverb ending in ly, nor use hyphens in a three-word unit modifier the first two elements of which are adverbs.
- eagerly awaited moment
- wholly owned subsidiary
- unusually well preserved specimen
- very well defined usage
- longer than usual lunch period
- still-lingering doubt
- not too distant future
- most often heard phrase
- but
- ever-normal granary
- ever-rising flood
- still-new car
- well-known lawyer
- well-kept secret
Proper nouns used as unit modifiers, either in their basic or derived form, retain their original form; but the hyphen is printed when combining forms.
- Latin American countries
- North Carolina roads
- a Mexican-American
- South American trade
- Spanish-American pride
- Winston-Salem festival
- African-American program
- Anglo-Saxon period
- Franco-Prussian War
- Seventh-day Adventists
- but
- Minneapolis-St. Paul region
- North American-South American sphere
- French-English descent
- Washington-Wilkes-Barre route or Washington/Wilkes-Barre route
- elderly clothesman
- old-clothes man
- competent shoemaker
- wooden-shoe maker
- field canning factory
- tomato-canning factory
- brave servicemen
- service men and women
- light blue hat (weight)
- light-blue hat (color)
- average taxpayer
- income-tax payer
- American flagship (military)
- American-flagship
- well-trained schoolteacher
- elementary school teacher
- preschool children (kindergarten)
- pre-school children (before school)
- rezoned wastesite
- hazardous-waste site
- but
- common stockholder
- stock ownership
- small businessman
- working men and women
- steam powerplant site
- meat packinghouse owner
- 2- to 3- and 4- to 5-ton trucks
- 2- by 4-inch boards, but boards 2 to 6 inches wide
- 8-, 10-, and 16-foot boards
- 6.4-, 3.1-, and 2-percent pay raises
- moss- and ivy-covered walls, not moss and ivy-covered walls
- long- and short-term money rates, not long and short-term money rates
but twofold or threefold, not two or threefold
- goat, sheep, and calf skins, not goat, sheep, and calfskins
- intrastate and intracity, not intra-state and -city
- American owned and managed companies
- preoperative and postoperative examination
- ante bellum days
- bona fide transaction
- ex officio member
- per capita tax
- per diem employee
- prima facie evidence
- abstract B pages
- article 3 provisions
- class II railroad
- grade A milk
- point 4 program
- ward D beds
- "blue sky" law
- "good neighbor" policy
- "tie-in" sale
- but
- right-to-work law
- line-item veto
- bluish green
- dark green
- orange red
- bluish-green feathers
- iron-gray sink
- silver-gray body
- big gray cat
- a fine old southern gentleman
- afterbirth
- Anglomania
- antedate
- antislavery
- biweekly
- bylaw
- circumnavigation
- cisalpine
- cooperate
- contraposition
- countercase
- deenergize
- demitasse
- excommunicate
- extracurricular
- foretell
- heroicomic
- hypersensitive
- hypoacid
- inbound
- infrared
- interview
- intraspinal
- introvert
- isometric
- macroanalysis
- mesothorax
- metagenesis
- microphone
- misstate
- monogram
- multicolor
- neophyte
- nonneutral
- offset
- outbake
- overactive
- pancosmic
- paracentric
- particoated
- peripatetic
- planoconvex
- polynodal
- postscript
- preexist
- proconsul
- pseudoscholastic
- reenact
- retrospect
- semiofficial
- stepfather
- subsecretary
- supermarket
- thermocouple
- transonic
- transship
- tricolor
- ultraviolet
- unnecessary
- underflow
- portable
- geography
- procurement
- coverage
- manhood
- innermost
- operate
- selfish
- partnership
- plebiscite
- pumpkin
- lonesome
- twenty fold
- meatless
- homestead
- spoonful
- outlet
- northward
- kilogram
- wavelike
- clockwise
- lifelike
- lilylike
- girllike
- bell-like
- Scotland-like
- McArtor-like
- anti-hog-cholera serum
- co-occurrence
- co-op
- mid-decade
- multi-ply (several plies)
- non-civil-service position
- non-tumor-bearing tissue
- pre-midcourse review
- pre-position (before)
- pro-choice
- pro-life
- re-cover (cover again)
- re-creation (create again)
- re-lay (lay again)
- re-sorting (sort again)
- re-treat (treat again)
- un-ionized
- un-uniformity
- but
- rereferred
- rereviewed
- re-redirect
- sub-subcommittee
- super-superlative
- ex-governor
- ex-serviceman
- ex-son-in-law
- ex-vice-president
- self-control
- self-educated
- quasi-academic
- quasi-argument
- quasi-corporation
- quasi-young
- but
- selfhood
- selfsame
Unless usage demands otherwise, use a hyphen to join a prefix or combining form to a capitalized word. (The hyphen is retained in words of this class set in caps.)
- anti-American
- pro-British
- un-American
- non-Government
- neo-Nazi
- post-World War II or post-Second World War
- non-Federal
- but
- nongovernmental
- overanglicize
- transatlantic
Print a hyphen between the elements of compound numbers from twenty-one to ninety-nine and in adjective compounds with a numerical first element.
- twenty-one
- twenty-first
- 6-footer
- 6-foot-ll-inch man
- 24-inch ruler
- 3-week vacation
- 8-hour day
- 10-minute delay
- 20th-century progress
- 3-to-l ratio
- 5-to-4vote
- .22-caliber cartridge
- 2-cent-per-pound tax
- four-in-hand tie
- three-and-twenty
- two-sided question
- multimillion-dollar fund
- 10-dollar-per-car tax
- thirty- (30-) day period
- but
- one hundred twenty-one
- 100-odd
- foursome
- threescore
- foursquare
- $20 million airfield
- second grade children
Print without a hyphen a modifier consisting of a possessive noun preceded by a numeral. (See also rule 8.14.)
- 1 month's layoff
- 3 weeks' vacation
- 1 week's pay
- 1 minute's delay
- 2 hours' work
but a 1-minute delay
Print a hyphen between the elements of a fraction, but omit it between the numerator and the denominator when the hyphen appears in either or in both.
- one-thousandth
- two-thirds
- two one-thousandths
- twenty-three thirtieths
- twenty-one thirty-seconds
- three-fourths of an inch
A unit modifier following and reading back to the word or words modified takes a hyphen and is printed in the singular.
- motor, alternating-current, 3-phase, 60-cycle, 115-volt
- glass jars: 5-gallon, 2-gallon, 1-quart
- belts: 2-inch, 1¼-inch, ½-inch, ¼-inch
Do not hyphenate a civil or military title denoting a single office, but print a double title with a hyphen.
- ambassador at large
- assistant attorney general
- commander in chief
- comptroller general
- Congressman at Large
- major general
- notary public
- secretary general
- secretary-treasurer
- sergeant at arms
- treasurer-manager
- under secretary
- but under-secretaryship
- vice president
- but vice-presidency
The adjectives elect and designate, as the last element of a title, require a hyphen.
- President-elect (Federal)
- ambassador-designate
- Vice-President-elect (Federal)
- minister-designate
- Secretary of Housing and Urban Development-designate
Do not print a hyphen in scientific terms (names of chemicals, diseases, animals, insects, plants) used as unit modifiers if no hyphen appears in their original form.
- carbon monoxide poisoning
- guinea pig raising
- hog cholera serum
- methyl bromide solution
- stem rust control
- equivalent uranium content
- whooping cough remedy
- but
- Russian-olive plantings
- Douglas-fir tree
Chemical elements used in combination with figures use a hyphen, except with superior figures.
- Freon-12
- polonium-210
- uranium-235
- U235
- Sr90
- 92U234
Note use of hyphens and closeup punctuation in chemical formulas.
- 9-nitroanthra(1,9,4,10)bis(1)oxathiazone-2,7-bisdioxide
- Cr-Ni-Mo
- 2,4-D
Print a hyphen between the elements of technical or contrived compound units of measurement.
- candela-hour
- crop-year
- horsepower-hour
- light-year
- passenger-mile
- staff-hour
- work-year
but kilowatthour
Print with a hyphen the elements of an improvised compound.
- blue-pencil (v.)
- 18-year-old (n., u.m.)
- know-it-all (n.)
- know-how (n.)
- lick-the-finger-and-test-the-wind economics
- make-believe (n., u.m.)
- one-man-one-vote principle
- roll-on/roll-off ship
- George "Pay-As-You-Go" Miller
- stick-in-the-mud (n.)
- let-George-do-it attitude
- how-to-be-beautiful course
- hard-and-fast rule
- penny-wise and pound-foolish policy
- first-come-first- served basis
but a basis of first come, first served
Use hyphens in a prepositional-phrase compound noun consisting of three or more words.
- cat-o'-nine-tails
- government-in-exile
- grant-in-aid
- jack-in-the-box
- man-of-war
- mother-in-law
- mother-of-pearl
- patent-in-fee
- but
- heir at law
- next of kin
- officer in charge
When the corresponding noun form is printed as separate words, the verb form is always hyphenated.
- cold-shoulder
- blue-pencil
- cross-brace
Print a hyphen in a compound formed of repetitive or conflicting terms and in a compound naming the same thing under two aspects.
- boogie-woogie
- comedy-ballet
- dead-alive
- devil-devil
- even-stephen
- farce-melodrama
- fiddle-faddle
- hanky-panky
- murder-suicide
- nitty-gritty
- pitter-patter
- razzle-dazzle
- walkie-talkie :nitwit
- willy-nilly
- young-old
- but
- bowwow
- dillydally
- hubbub
- riffraff
Use a hyphen in a nonliteral compound expression containing an apostrophe in its first element.
- asses'-eyes
- ass's-foot
- bull's-eye
- cat's-paw
- crow's-nest
Use a hyphen to join a single capital letter to a noun or a participle.
- H-bomb
- I-beam
- T-shaped
- U-boat
- C-chip
- C-section
- V-necked
- S-iron
- T-square
- X-ed out
- but
- x ray
- x raying
- S turns
Print idiomatic phrases without hyphens.
- come by
- inasmuch as
- insofar as
- Monday week
- nowadays