In a previous post, we talked about how to form plural nouns, some of the different ways singular nouns become plural in English, and some of the exceptions to the rules. For one-word nouns, the methods are fairly straightforward, but things can get a little tricky when you’re dealing with compound nouns. Here are some examples:

If the noun is at the end of a phrase, pluralize the noun as if it were not modified by the preceding phrase. In this case, it’s only a “compound noun” because we’re looking at the noun as part of the phrase rather than by itself.

a qualified candidate / the qualified candidates
a significant gain / many significant gains
one black sheep / six black sheep
one distant glowing nebula / two distant glowing nebulae

If the noun remains at the beginning of the phrase rather than at the end, then you still make the noun plural while leaving the rest alone, even if that looks or sounds odd to you. This rule holds whether you’re hyphenating the phrase or not.

my brother-in-law / the brothers-in-law of the widow
the attorney general / attorneys general in the past
a head of state / those heads of state
one passer-by / two passers-by (also passerby / passersby)
the notary public / future notaries public

If the compound noun is one word, treat it as such and form the plural with the last noun in the compound word, following the standard rules.

the housewife / several housewives
a blackboard / many blackboards
one firefly / two fireflies

Compounding the problem is the matter of adding the possessive -s to these pluralized compound nouns. For example, if you were talking about the anti-smoking initiatives in the United States, you might say that current laws follow previous Surgeons General’s recommendations but that’s an extremely awkward phrase to write, read, and say. Avoid these problems by phrasing such a statement as current laws follow the recommendations of previous Surgeons General.

Do you have one or more questions about compound nouns or other aspects of English vocabulary? Leave your questions in the comments.