Well, rats. Yesterday whilst perusing the book block for no real reason I came across a word that should have been replaced long, long ago but has somehow through the editing process clung like a hair to the proverbial shower tile. Worse, the word means exactly the opposite of what its paragraph describes—a remnant from way back, when that particular passage had been written the other way around.
Too late to change it now, so it'll be noted for second-printing changes if such a thing ever comes to pass. My editor consoled me, saying if everyone else missed it, chances are most others would, too.
Maybe I should start a contest and offer a prize for the first person who spots it.