The Collaborative International Dictionary of English v.0.48:

Rosin \Ros"in\, n. [A variant of resin.]
   The hard, amber-colored resin left after distilling off the
   volatile oil of turpentine; colophony.
   [1913 Webster]

   Rosin oil, an oil obtained from the resin of the pine tree,
      -- used by painters and for lubricating machinery, etc.
      [1913 Webster]