Further vs Farther

HOW do we use the words “further” and “farther” ?
– T.F. Chan

Both “further” and “farther” are the comparative forms of the adjective and adverb “far”. As adjectives, they mean “more distant”. As adverbs, they mean “at or to a greater distance”. They can be used interchangeably in sentences like:

“Her house is further/farther from the school than mine is.” (as adjectives)
“He was so exhausted, he couldn’t run any further/farther.” (as adverbs)

However, “further” has more meanings than “farther”. The adjective “further” can mean “additional”. For example, we can say: “Since we have come to an agreement, there shall be no further discussion on the matter.”

The adverb “further” can mean “to a greater degree or extent”, e.g. in “We must think further about this matter before we make a decision.”

It can also mean “in addition to what has just been said” (Oxford Advanced Learner’s Dictionary), e.g. “We’ve chosen to buy this house because of its size, appearance and price. Further, it is in a very pleasant location.”