An occasional Halloween prank in the US is “egging” where kids throw eggs at a house or a car. Their friends, you might imagine, are busy “egging them on.” But egging someone on, even when you’re egging them on about egging, has nothing to do with eggs. Well, I mean, in that particular case I suppose it does. But in general, egging someone on doesn’t involve eggs. In fact the “egg” involved is a completely different word.
“Egg” comes from Old English, where it was “ǽg” but probably sounded pretty much like it does today. It’s pretty ancient; before Old English even existed, the word was spoken in various Germanic languages. In all those centuries, there have never been any variations in what it means.
But then around the year 1000 or so, the Old Norse word “eggja” entered English, where it was shortened to “egg” — so then there were two nearly identical words. “Eggja” meant to urge, and until around the 1500s that’s exactly how it was used: “Þe clergi of Scotland egged þer kyng Jon” (1330). At that point the word began to be paired with “on:” “Ile egge them on to speake some thyng…” (1566). It became more and more common to use the phrase “egg on,” and using “egg” by itself pretty much died out by the 1700s. Unless you were, you know, talking about actual eggs.
It wasn’t until the 1800s that “egging” (the tossing of actual eggs) was ever mentioned. For one thing, eggs were probably too valuable to waste before that. For another, I’m not sure anybody would have noticed or cared about a stain on their hut during earlier times. But luckily, by the time there was such a thing as “egging” (the egg kind), “egging” (the urging kind) was always paired with “on”, so that was one less thing to be confused about. I mean, except for an accident of historical timing, we might have had to cope with sentences like “no egghead, he was a bad egg who egged egging.”
