Further and farther are two terms that are commonly used interchangeably in everyday speech. Even though the terms have similar meanings, there is a difference between them. The term further is used primarily when referring to figurative or abstract distances, while farther is used to describe literal or physical distances.
The term further implies an extension of something that has already been established. It is used to describe abstract concepts such as time, effort, and knowledge, or figurative distances such as degree and level. Consider the following sentence: “She is further along in her studies than I am.” Here, the word further is used to describe the degree or level of knowledge of the two people in question.
On the other hand, the term farther is used to describe literal or physical distances. It is used to describe the amount of space between two points and is always associated with a specific direction. Consider the following sentence: “I need to drive farther north to get to my destination.” Here, the word farther is used to describe the physical distance that needs to be covered in a particular direction.
In summary, further and farther are two terms that are used to describe distances. However, the term further is used to describe figurative or abstract distances, while farther is used to describe literal or physical distances.