A Word, Please: You say ‘indices,’ she says ‘indexes’

On the day I’m writing this, I’m about 3% wealthier than I was the day before, when I was about 5% wealthier than the day before, at which point I was about 10% poorer than I was the day before that.

I watch the stock market a lot. I’m not sure why. It’s not like I have much money. I suppose those “Real Housewives”-type reality TV shows just aren’t insanely dysfunctional enough to hold my attention. After all, on those, people only pull out each other’s hair.

But the Dow Jones Industrial Average — now that’s drama.

By following the nauseating ups and downs, I’ve learned a few things. I even have a hot stock tip to share: Any company that makes barrels with suspenders attached is a definite “buy.”

Another thing I’ve learned is that news outlets don’t agree on what the plural of “index” should be. For example, on a recent NBC Nightly News segment, anchor Brian Williams made reference to all three of the major stock indexes. But the next day, an NPR reporter talked about the three major indices.

So who’s right?

In English, the standard way to form a plural is by either adding S or, if the singular word ends in S or a similar sound, like X, by adding ES. Of course, English has a number of words that form their plural according to the rules of some other language. For example, the plural of phenomenon is usually phenomena and not phenomenons.

English even has a lot of foreign-language-based plurals that actually are more familiar to us than their singular forms. Paparazzi, criteria, data, panini and bacteria have singular forms we seldom use: paparazzo, criterion, datum, panino and bacterium.

But “index” is unusual in that people regularly form its plural two different ways. Seems almost as many people use “indexes” as “indices.” So which is right? And, more important: How, when it’s crucial you get it right, can you be sure?

The key to forming plurals perfectly every time is a lot closer at hand than you may know. It’s right in the dictionary.

Many people don’t realize that dictionaries are comprehensive sources for plural formation because a lot of dictionary entries don’t contain plural forms. For example, if you look up “cat” in most dictionaries, you see no indication that the plural is “cats.” But that’s because it’s a regular noun.

As any good dictionary explains in its “How to use this dictionary” section up front, the plurals of regular nouns are not spelled out. That section will tell you that, unless specified otherwise, the plural is formed the regular way, by adding S or ES.

But irregular plurals are spelled out. So under “man,” you see “men.” At the entry for “goose,” you see “geese.”

If a word has more than one plural form recognized by the dictionary, both forms will be included. For example, “Webster’s New World College Dictionary’s” listing for “index” offers you the choice of “indexes” or “indices.” That tells you that either one is correct.

But what if you really need to be sure you’re making the best, most correct choice? How can you know which to use?

Actually, if you know how to use your dictionary, that’s easy. Dictionaries customarily list their preferred forms first. So because “Webster’s New World College Dictionary” lists indexes before indices, we know that’s the one it recommends. And, by the way, the “American Heritage Dictionary” and “Merriam-Webster’s Collegiate Dictionary” agree.

So NPR’s choice was fine, but Brian Williams’ was better. Now if only they could tell us what to do with our money.

JUNE CASAGRANDE is author of “It Was the Best of Sentences, It Was the Worst of Sentences.” She can be reached at JuneTCN@aol.com.