The Collaborative International Dictionary of English v.0.48:

Furnish \Fur"nish\ (f[^u]r"n[i^]sh), v. t. [imp. & p. p.
   Furnished; p. pr. & vb. n. Furnishing.] [OF. furnir,
   fornir, to furnish, finish, F. fournir; akin to Pr. formir,
   furmir, fromir, to accomplish, satisfy, fr. OHG. frumjan to
   further, execute, do, akin to E. frame. See Frame, v. t.,
   and -ish.]
   1. To supply with anything necessary, useful, or appropriate;
      to provide; to equip; to fit out, or fit up; to adorn; as,
      to furnish a family with provisions; to furnish one with
      arms for defense; to furnish a Cable; to furnish the mind
      with ideas; to furnish one with knowledge or principles;
      to furnish an expedition or enterprise, a room or a house.
      [1913 Webster]

            That the man of God may be perfect, thoroughly
            furnished
            unto all good works.                  --2 Tim. iii.
                                                  17,
      [1913 Webster]

   2. To offer for use; to provide (something); to give
      (something); to afford; as, to furnish food to the hungry:
      to furnish arms for defense.
      [1913 Webster]

            Ye are they . . . that furnish the drink offering
            unto that number.                     --Is. lxv. 11.
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            His writings and his life furnish abundant proofs
            that he was not a man of strong sense. --Macaulay.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Furnish \Fur"nish\, n.
   That which is furnished as a specimen; a sample; a supply.
   [Obs.] --Greene.
   [1913 Webster]

WordNet (r) 3.0 (2006):

furnish
    v 1: give something useful or necessary to; "We provided the
         room with an electrical heater" [syn: supply, provide,
         render, furnish]
    2: provide or equip with furniture; "We furnished the house in
       the Biedermeyer style"

Moby Thesaurus II by Grady Ward, 1.0:

85 Moby Thesaurus words for "furnish":
   accommodate, accommodate with, accouter, adapt, adjust, afford,
   apparel, appoint, arm, array, attune, bear, bear fruit,
   bring forth, capacitate, clothe, condition, contribute, decorate,
   deliver, dispense, donate, dower, dress, enable, endow, endue,
   equip, favor with, feed, fill, fill up, find, fit, fit out, fit up,
   fructify, fruit, fund, gear, give, hand, hand over, heap upon,
   heel, indulge with, invest, keep, lavish upon, maintain,
   make available, make provision for, man, mount, munition, outfit,
   pour on, prepare, present, produce, provide, provide for,
   provision, put in trim, put in tune, qualify, recruit, replenish,
   rig, rig out, rig up, shower down upon, staff, stock, stock up,
   store, subsidize, suit, supply, support, transfer, tune, turn out,
   turn over, yield