The Collaborative International Dictionary of English v.0.48:

Thitsee \Thit"see\, n. [Written also theesee, and thietsie.]
   1. (Bot.) The varnish tree of Burmah (Melanorrhoea
      usitatissima).
      [1913 Webster]

   2. A black varnish obtained from the tree.
      [1913 Webster]