Further, v. t. [imp. & p. p. Furthered; p. pr. & vb. n. Furthering.]
Etymology: [OE. furthren, forthren, AS. fyredhran, fyredhrian. See Further, adv.]
To help forward; to promote; to advance; to forward; to help or assist. This binds thee, then, to further my design. Dryden. I should nothing further the weal public. Robynsom (More's Utopia).
2 other Webster entries under this spelling
Further, adv.
To a greater distance; in addition; moreover. See Farther. Carries us, I know not how much further, into familiar company. M. Arnold. They sdvanced us far as Eleusis and Thria; but no further. Jowett (Thucyd. ). Further off, not so near; apart by a greater distance.
Further, a. compar. [Positive wanting; superl. Furthest.]
1. More remote; at a greater distance; more in advance; farther; as, the further end of the field. See Farther.
2. Beyond; additional; as, a further reason for this opinion; nothing further to suggest.
Note: The forms further and farther are in general not differentiated by writers, but further is preferred by many when application to quantity or degree is implied.
Shades of meaning
Fernald has no entry of its own for further; he lists it under but, promote, quicken, yet.
He lists it without comment; the entries above explain its neighbors.