Hyphens, Compounds, and Where They Change Meaning

The rule is about the reader, not about the words

The Government Publishing Office states the purpose directly. A hyphen is a mark of punctuation that not only unites but also separates the component words. It facilitates understanding, aids readability, and ensures correct pronunciation.¹

From that follow the two rules that do most of the work. The general rule is to omit the hyphen when words appear in regular order and the omission causes no ambiguity in sense or sound.¹ The unit-modifier rule is to print a hyphen between words combined to form a unit modifier immediately preceding the word modified, particularly where one element is a present or past participle.¹

High-speed line takes the hyphen because high modifies speed rather than line, and the hyphen says so. Atomic energy power does not, because no reader was going to misassemble it.

Chicago arrives at the same place by a different route. Compound modifiers are hyphenated when they precede the noun they modify, and many of the same terms are left open when they follow it. Hyphens are retained for clarity where a compound modifier is separated from its noun by an intervening phrase, to stop a reader from momentarily misreading the relationship.²

The three places a hyphen changes meaning rather than appearance

Most hyphenation is house style, settled by the manual and recorded on a style sheet. The three below are not.

The first is a compound whose parts could attach differently. A small business owner and a small-business owner describe different people, and only the hyphen distinguishes them. So do a man eating fish and a man-eating fish.

The second is a number attached to a unit before a noun. The GPO gives the pair directly: a 4-percent increase takes hyphens, while 4 percent interest does not, and it explains that the difference turns on whether an article is present and of is understood.¹

The third is a suspended compound in a list. First- and second-year students needs its first hyphen to work, and dropping it changes what the sentence says about the first group.

Everything else is the manual's preference, and the manual will say which way it goes. The three above are decided by the sentence rather than by the manual.

Two rules that stop over-hyphenation

The GPO includes a restraint that authors rarely apply. Where meaning is clear and readability is not aided, it is not necessary to use a hyphen to form a temporary compound. Restraint should be exercised in forming unnecessary combinations of words used in normal sequence.¹

It also excludes cases that catch careful writers. A two-word unit modifier whose first element is an adverb ending in ly takes no hyphen. A unit modifier already enclosed in quotation marks takes none. A compound predicate adjective whose second element is a past participle takes none.¹

The last of those is the one that produces the most unnecessary marks. A hyphen that belongs before the noun does not automatically belong after it.

Why this is a style-sheet problem more than a grammar problem

The GPO says the rules are somewhat flexible and that exceptions must be allowed. It adds that word forms constantly undergo modification, with hyphenated compounds tending to lose the hyphen over time.¹

That is an unusual admission for a style manual, and it has a practical consequence. A manuscript cannot resolve hyphenation by consulting an authority alone, because the authority expects judgment. What it can do is decide each recurring compound once and record the decision.

Editors Canada places exactly that inside copy editing. The standard covers maintaining a style sheet that tracks abbreviations, the treatment of numbers, and vernacular usages, and resolving variations in terminology, logic, and mechanics.³ A book that hyphenates a compound in chapter one and leaves it open in chapter nine has a fault no manual is needed to identify.

What EditFast does with it

Editors Canada includes checking mechanical consistency and developing the style sheet within its definition of copy editing, which is where hyphenation decisions live.⁴ We apply whichever manual a client has named, decide the compounds that manual leaves open, record every one on the style sheet, and return the sheet with the manuscript. Where a hyphen changes the meaning rather than the appearance, we query rather than choose.

Everything a client sends is treated in confidence, including drafts, style sheets, and correspondence. Grammar and style work is quoted on the whole document.

An author who wants to spend ten minutes on this can search their manuscript for the compounds they use most and see how many spellings come back. The number is usually higher than expected, and it is the whole of the problem.