Right. Hone means to sharpen, make more effective. You probably never see this mistake. But when you go the other way, you see it and hear it a lot: hone in on the target. It's supposed to be home in. Or at least that's how I learned it. Here's what Merriam-Webster.com has to say about it:
"The few commentators who have noticed hone in consider it to be a mistake for home in. It may have arisen from home in by the weakening of the \m\ sound to \n\ or may perhaps simply be due to the influence of hone. Though it seems to have established itself in American English (and mention in a British usage book suggests it is used in British English too), your use of it especially in writing is likely to be called a mistake. Home in or in figurative use zero in does nicely."
And so here should begin a discussion about prescriptivism vs. descriptivism -- prescriptive dictionaries being those that tell you what's "right," and descriptive those that show you what is being used the most. If a word or phrase is being used a lot, even in what was originally considered an incorrect manner, it will appear in a descriptive dictionary because it's really a record of language as it's being used. It's hard to say what constitutes prescriptivism, since language always is, and needs to be, changing -- so who's to say what's right or wrong? When we declare, "It's in the dictionary, so it's right," we act as if it's the edict of some omniscient being. But if it shows up in the dictionary (as does, my 8-year-old likes to tell me, the word ain't), it's either the original form of the word, the popular form, a brand-new word, or sometimes all of the above.
That's why it's a good idea to read the full definition to get any usage notes that might be included, as the one above. For me, a language purist who seldom follows the crowd, it's still going to be home in. Or, better yet, zero in.