However, this is not the usual way to use the word “hone.” Normally, you hone your skills — that is, make more acute or effective, improve, or perfect.
Hone can also mean “to sharpen on a hone” (thanks, dictionary, that was really helpful!) No, seriously, a hone is a whetstone, or sharpening tool:
Many who care about language say that “hone in” is a mistake — the speaker really means “home in.” However, over time, the two phrases have started to merge. Here is one explanation:
The original is from early aeronautics. Pilots were guided to their destinations and back to their home bases by radio beacons. In the jargon of the time ” the early 1920s ” they were said to home on the beacons. This was clearly taken from the somewhat older expression homing pigeons. In later years, beacons were fitted to aircraft so one could home on another. By this time ” around 1940 ” home had lost much of its literal association with going home and had taken on the figurative idea of guiding an aircraft to its target or destination by means of a radio signal.
…After the war, people began to use it in the current figurative sense of focusing one’s attention on a single matter.
That’s now the only situation in which most people encounter it. It’s hardly obvious to somebody who hasn’t come across it before or who doesn’t know the background. Why home? This lack of context makes it easy for speakers to change the word into something that seems to be more appropriate or make more sense. Hone in on is a classic example of the type of word shift that has become known in recent years among linguists as an eggcorn: a change in word form due to error or misunderstanding.
In this case, it seems to be the figurative sense of the verb to hone, meaning to sharpen a tool, that has led to the change, since it’s widely used to mean making something work better, for example when we say somebody is honing her skills.
A final word from Merriam-Webster:
Though “home in” 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.