farthest

To the greatest distance in space or time (`farthest' is used more often than `furthest' in this physical sense).

“see who could jump the farthest”

“chose the farthest seat from the door”

To the greatest degree or extent or most advanced stage (`furthest' is used more often than `farthest' in this abstract sense).

“she goes farthest in helping us”

(comparatives of `far') most remote in space or time or order.

“had traveled to the farthest frontier”