When I first released Clytie's Caller, I found myself surprised by a review that said I repeatedly misspelled the same word. I looked and looked, running spell checker, reading the manuscript back to front ... all of the usual things. It took me a while, but I finally figured out that the reviewer was referring to this word: nuncheon.
Believe it or not, we didn't always call the noon meal lunch or luncheon. During the Regency period, during which I set the book, the meal was referred to as nuncheon. It comes from the word none, meaning mid-day, or (you guessed it) noon. The word "lunch" was considered vulgar at the time; it was something only workmen would have said. It was only over time that nuncheon was replaced with luncheon, or what we now call lunch -- at least on the West Coast of the United States. My East Coast family members still refer to breakfast, dinner (the noon meal), and supper.
One of the things I enjoy most in my research is learning how people would have spoken and what words they would have used. This example is a favorite.