If I had to chart the times writers have asked about the differences between these two words, it’d be, well, off the chart.

“Indices” is the plural of index, which makes it a noun. For example: “The politician presented several economic indices to prove we’re still in a recession.”

“Indexes” is the present tense of the verb “index.” To wit, “Jane indexes her DVDs alphabetically.”

This all may be changing, though. The Wall Street Journal’s stylebook says using “indexes” as a plural of “index” is acceptable, and many spell checks will tell you that “indices” is wrong.

Over time, we’ll probably see usage of “indices” fall to an all-time low.