Last week in the course of our homeschool day, somehow or another we got talking about what our different fingers are called, and my clever little Xoe asked me why the pointer finger is also called the index finger.

Closeup from Michelangelo’s Creation of Adam

Insert Mommy going, “Um…because…maybe…it’s the one you trail down the page of an index when you’re looking for something?” LOL. At which point I added, “Don’t believe that, I’m making it up. Let’s look and see.” And so we did. =)

Index has meant “the pointer finger” since the 14th century. It comes directly from Latin, and the literal meaning is “that which points out.” So of course, it makes sense for the finger…and it also makes sense for the index in a book, a meaning which came along by the 1570s. Old in its own right, to be sure! So while the two are very directly related, coming from the same meaning of the same word, one didn’t derive from the other, but rather from the root. So I quickly corrected my guess, LOL.

More derivative meanings (like “cost-of-living index” or “heat index”) come from the sense of “indicator” that the word carries and started popping up in the 1800s.

Hope everyone has a great week!