Merriam-Webster's Collegiate® Dictionary, 11th Edition
FURTHER
I. adverb
Etymology: Middle English, from Old English furthor (akin to Old High German furthar further), comparative, from the base of Old English forth forth Date: before 12th century farther 1 , in addition ; moreover , to a greater degree or extent , see: farther
II. transitive verb (furthered; furthering) Date: before 12th century to help forward ; promote , see: advance furtherer noun
III. adjective
Date: 13th century
farther 1 , going or extending beyond ; additional , see: farther