Source : Webster's Revised Unabridged Dictionary (1913)

Japan \Ja*pan"\, a.
   Of or pertaining to Japan, or to the lacquered work of that
   country; as, Japan ware.

   {Japan allspice} (Bot.), a spiny shrub from Japan
      ({Chimonanthus fragrans}), related to the Carolina
      allspice.

   {Japan black} (Chem.), a quickly drying black lacquer or
      varnish, consisting essentially of asphaltum dissolved in
      naphtha or turpentine, and used for coating ironwork; --
      called also {Brunswick black}, {Japan lacquer}, or simply
      {Japan}.

   {Japan camphor}, ordinary camphor brought from China or
      Japan, as distinguished from the rare variety called
      borneol or Borneo camphor.

   {Japan clover}, or {Japan pea} (Bot.), a cloverlike plant
      ({Lespedeza striata}) from Eastern Asia, useful for
      fodder, first noticed in the Southern United States about
      1860, but now become very common. During the Civil War it
      was called variously {Yankee clover} and {Rebel clover}.
      

   {Japan earth}. See {Catechu}.

   {Japan ink}, a kind of writing ink, of a deep, glossy black
      when dry.

   {Japan varnish}, a varnish prepared from the milky juice of
      the {Rhus vernix}, a small Japanese tree related to the
      poison sumac.

Source : WordNet®

Rhus vernix
     n : smooth American swamp shrub with pinnate leaves and greenish
         flowers followed by greenish white berries; yields an
         irritating oil [syn: {poison ash}, {poison dogwood}, {poison
         sumac}, {Toxicodendron vernix}]