Chew On This

Sometimes the source of a word is right there in front of your eyes, and you just can't see it; then when you find out the answer, you don't really have any choice but to whack yourself on the forehead with the heel of your hand.

The word "corrosion" popped into my head, although I can't think why--I think it was on the bus to the airport in Toronto the other day--and while I was very sure that the first part was a variation of the usual intensifying prefix "com-" ("thoroughly; completely"), I couldn't make any sense of what was pretty obviously the root of the word, "-rode". Other than its being Latin, I couldn't get any further. As it turns out, it's so obvious that I'm a little ashamed I didn't think of it. Care to have a go at it?

Well, as it turns out, the root comes from the verb "rodere", which means "to gnaw". And what gnaws and has a name that looks like "rodere"? A rodent. Obviously.

"Rodere" comes from the Indo-European root "red-", which led to a little batch of other words in English which all carry the sense of gnawing, scratching, or scraping. "Razor" is one of them, and also the intimately related "erase" (originally to scrape from the surface of a parchment) and "raze" (to scrape down level with the earth). The cheese dish called raclette is melted on a sort of flat pan and scraped onto bread. A rostrum is a speaker's platform or ship's prow: it projects out from a surface like the beak of a bird, which is what "rostrum" originally meant in Latin, and a beak is used for gnawing and biting.

"Rake", surprisingly, is not one of the offspring of "red-": it comes instead from Latin "recti-", "straight", because it was originally made of little straight pieces of wood.