Copyediting: The mysterious middle s

I haven’t blogged on a copyediting topic since April, so it’s well past time. Today’s subject: plural formation.

Because of its mixed ancestry, the English language makes nouns plural in numerous ways. Plurals could provide grist for many weeks of entries. Today, I’ll focus on an often overlooked, often confusing class of nouns: compound nouns.

Compound words are just what they sound like: two or more words stuck together to mean a single concept.

Some compound nouns are easy to punctuate. Doghouse, skyscraper, teaspoonful, breakthrough, and city council all take a final “s”: doghouses, skyscrapers, teaspoonfuls, breakthroughs, city councils.

Others are tricky. They may take an “s,” but not at the end. Examples are:
•fleur de lis —> fleurs de lis (although fleur de lis is an alternative plural)
•passerby —> passersby
•surgeon general —> surgeons general
•attorney general —> attorneys general
•pâté de foie gras —> pâtés de fois gras
•mother-in-law —> mothers-in-law
•coup d’état —> coups d’état
•chief of staff —> chiefs of staff

How do you know where to put the “s” in a compound word? The easiest way is to check the electronic dictionary on your computer or the hardcopy that sits by your side. (You do keep at least one dictionary always at hand, right?)

Alternatively, follow the rule given by The Associated Press Stylebook and The New York Times Manual of Style and Usage: Add the “s” to the most important word in a multiword compound noun. Of course, then you have to decide which word is most important.

Or try the lazy way. If you look at most compound nouns, you’ll find that only one of the words in it is a noun. If you add the “s” to the end of the noun, you’ll usually be right.

There are exceptions, though, to the lazy way. For example, compound nouns that end in ”ful” use an “s” at the end: handfuls, cupfuls. Your ear will usually be able to tell you when you have the "s" in the wrong place.