The Collaborative International Dictionary of English v.0.48:

Varnish \Var"nish\, n. [OE. vernish, F. vernis, LL. vernicium;
   akin to F. vernir to varnish, fr. (assumed) LL. vitrinire to
   glaze, from LL. vitrinus glassy, fr. L. vitrum glass. See
   Vitreous.]
   [1913 Webster]
   1. A viscid liquid, consisting of a solution of resinous
      matter in an oil or a volatile liquid, laid on work with a
      brush, or otherwise. When applied the varnish soon dries,
      either by evaporation or chemical action, and the resinous
      part forms thus a smooth, hard surface, with a beautiful
      gloss, capable of resisting, to a greater or less degree,
      the influences of air and moisture.
      [1913 Webster]

   Note: According to the sorts of solvents employed, the
         ordinary kinds of varnish are divided into three
         classes: spirit, turpentine, and oil varnishes.
         --Encyc. Brit
         [1913 Webster]

   2. That which resembles varnish, either naturally or
      artificially; a glossy appearance.
      [1913 Webster]

            The varnish of the holly and ivy.     --Macaulay.
      [1913 Webster]

   3. An artificial covering to give a fair appearance to any
      act or conduct; outside show; gloss.
      [1913 Webster]

            And set a double varnish on the fame
            The Frenchman gave you.               --Shak.
      [1913 Webster]

   Varnish tree (Bot.), a tree or shrub from the juice or
      resin of which varnish is made, as some species of the
      genus Rhus, especially Rhus vernicifera of Japan. The
      black varnish of Burmah is obtained from the
      Melanorrh[oe]a usitatissima, a tall East Indian tree of
      the Cashew family. See Copal, and Mastic.
      [1913 Webster]

WordNet (r) 3.0 (2006):

varnish tree
    n 1: large tree native to southeastern Asia; the nuts yield oil
         used in varnishes; nut kernels strung together are used
         locally as candles [syn: candlenut, varnish tree,
         Aleurites moluccana]
    2: small Asiatic tree yielding a toxic exudate from which
       lacquer is obtained [syn: varnish tree, lacquer tree,
       Chinese lacquer tree, Japanese lacquer tree, Japanese
       varnish tree, Japanese sumac, Toxicodendron
       vernicifluum, Rhus verniciflua]