Why do we not use hyphens in "school bus maintenance" or "furniture factory pay cut protest"?
"school bus" is a compound adjective so why not "school-bus"? Especially since I think "school bus maintance" can be understood as the maintenance of ordinary buses that takes place at school.
And if the answer is "school bus" is a super common phrase then note that "furniture factory pay cut" is less common.
A guide for using hyphens with compound adjectives:
General Principle 1 If a compound adjective can be misread, use a hyphen.
General Principle 2 In a temporary compound that is used as an adjective before a noun, use a hyphen if the term can be misread or if the term expresses a single thought (i.e., all words together modify the noun
For example:
"the adolescents resided in two parent homes" means that two homes served as residences, whereas if the adolescents resided in "two-parent homes," they each would live in a household headed by two parents. A properly placed hyphen helps the reader understand the intended meaning.
Also use hyphens for
Compounds in which the base word is
capitalized:
pro-Freudian
a number: post-1970
an abbreviation: pre-UCS trial
more than one word: non-achievement-oriented students
All "self-" compounds whether they are adjectives or nouns
self-report self-esteem the test was self-paced Exception: self psychology
Words that could be misunderstood
re-pair [pair again]
re-form [form again]
un-ionized
Words in which the prefix ends and the base word begins with the same vowel
meta-analysis
anti-intellectual
co-occur
General Principle 3
Most compound adjective rules are applicable only when the compound adjective precedes the term it modifies. If a compound adjective follows the term, do not use a hyphen, because relationships are sufficiently clear without one.
client-centered counseling
but
the counseling was client centered
t-test results
but
results from t tests
same-sex children
but
children of the same sex
General Principle 4
Write most words formed with prefixes and suffixes as one word.
Prefixes
aftereffect
extracurricular
multiphase
socioeconomic
Suffixes
agoraphobia
wavelike
cardiogram
General Principle 5
When two or more compound modifiers have a common base, this base is sometimes omitted in all except the last modifier, but the hyphens are retained.
Long- and short-term memory
2-, 3-, and 10-min trials
See the Publication Manual for exceptions to these principles.
(adapted from the sixth edition of the APA Publication Manual, © 2010)
If the term had been only: furniture factory pay cut, I would not use a hyphen.
pay cut is a standalone term but when used as used above, a hyphen makes reading easier.
Hyphens are a writing/printing convention and rather arbitrary. But the general rule of thumb (not a grammatical rule) for most of the 20th century was that when the attributive adjective + noun combination was generally perceived to be approaching single word status but was not quite a "compound noun", it would be hyphenated to signal its almost-thereness.
When a two-element word has attained true single-word status it is written or typeset as one word (sunshine, schoolhouse).
