farther (adj.) Look up farther at Dictionary.com
c.1300, variant of further (q.v.), by 17c. it replaced ferrer as comparative of the descendant of Old English fierr "far" (itself a comparative but no longer felt as one). Vowel change influenced by the root vowel, and confusion with Middle English ferþeren "to assist, promote, advance" (see forth). There is no historical basis for the notion that farther is of physical distance and further of degree or quality.