The Collaborative International Dictionary of English v.0.48:

Japan \Ja*pan"\, a.
   Of or pertaining to Japan, or to the lacquered work of that
   country; as, Japan ware.
   [1913 Webster]

   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.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Lespedeza striata
    n 1: an annual of tropical Asia naturalized in United States
         [syn: japanese clover, japan clover, jap clover,
         Lespedeza striata]