I recently got some feedback in a critique group regarding the correct usage of further and farther. Naturally, since I learned something new, I wanted to share it with you (as I do).
According to Woodward English, the correct usage of farthest is when referring to distance only. Furthest, on the other hand, can be used for various purposes. Even Grammar Girl says, “If you can’t decide which one to use, you’re safer using further because farther has some restrictions.” And just because I like to be thorough, I checked the Oxford Dictionaries as well. Originally, further and furthest were restricted to abstract use, but not anymore.
Now we know. 🙂