Source : Webster's Revised Unabridged Dictionary (1913)

Quassin \Quas"sin\, n. [Cf. F. quassine. See {Quassia}.] (Chem.)
   The bitter principle of quassia, extracted as a white
   crystalline substance; -- formerly called {quassite}.
   [Written also {quass[=i]in}, and {quassine}.]