late 14c., "front;" variant of further (adj.). From 1510s as "additional;" 1560s as "more remote."
farther (adv.)
15c. alteration of Middle English ferther (c. 1300), a variant of further (adv.). There is no historical basis for the notion that farther is of physical distance and further of degree or quality.
实用例句
1. Both of my sisters moved even farther away from home.
我的两个姐姐都搬得离家更远了。
来自柯林斯例句
2. I can't see any farther than the next six months.
6个月以后的事情我就无法预见了。
来自柯林斯例句
3. She set her glass down and slid farther under the covers.
她放下杯子，钻进被子里。
来自柯林斯例句
4. Staff who have to travel farther can claim excess travel expenses.