farther in WordNet English dictionary

1. to or at a greater distance in time or space (`farther' is used more frequently than `further' in this physical sense)
   "farther north"; "moved farther away"; "farther down the corridor"; "the practice may go back still farther to the Druids"; "went only three miles further"; "further in the future"
   farther  further  farther  further 
   
2. to or at a greater extent or degree or a more advanced stage (`further' is used more often than `farther' in this abstract sense)
   "further complicated by uncertainty about the future"; "let's not discuss it further"; "nothing could be further from the truth"; "they are further along in their research than we expected"; "the application of the law was extended farther"; "he is going no farther in his studies"
   further  farther  further  farther 
   

1. more distant in especially space or time
   "they live in the farther house"
   farther 
   
2. more distant in especially degree
   "nothing could be further from the truth"; "further from our expectations"; "farther from the truth"; "farther from our expectations"
   further  farther