plural acronyms

A few weeks ago, I was in New Orleans for Jazzfest, and while I was mostly off the clock, I did catch this typo on a sign while I was waiting for Allen Toussaint to start his set. For some reason, people tend to think these types of acronyms (CD, DVD, MRI, WMD) need an apostrophe to make them plural. But they don’t — the correct plural form is CDs.

basic plural possessives

This is a phenomenon I see all the time when I’m shopping (which is a lot). I try not to get too exasperated about grammar mistakes — the fact that they’re so common keeps me in business — but I honestly don’t understand why this is such a common error. “Girl” doesn’t end in “s,” or a vowel, two things that can trip people up when it comes to employing the possessive. This is a simple rule: If something belongs to a collective, you use the plural form, followed by an apostrophe (girls’).

Oddly enough, all the other signs in the store were correct, including “Women’s” and “Men’s” which seem to have more potential for confusion. I don’t get it.