Because I learned it in third year primary and I know that there are standardized tests in most middle schools now. I had an interesting time when I first encountered those.
@YamiCuoreLarouxI'm also surprised I havent said it in science class,I've said the smartest words of my life in that class,even came up with a hypothesis involving the inside of a black hole earlier today
Well, it's probably more of a reading/literature/English (I don't even know what most schools call them now...) class word, actually, so maybe that's it. I can see it maybe being used in a few situations, though.
Either way, now you know! Use this new power wisely.