FARTHEST — СИНОНІМІЯ
farthest (comparatives of `far'') most remote in space or time or order
WordNet
farthest to the greatest distance in space or time (`farthest'' is used more often than `furthest'' in this physical sense)
WordNet
farthest to the greatest degree or extent or most advanced stage (`furthest'' is used more often than `farthest'' in this abstract sense)
WordNet