Source : Webster's Revised Unabridged Dictionary (1913)

Lupulin \Lu"pu*lin\, n. [Cf. F. lupulin. See {Lupuline}.]
   1. (Chem.) A bitter principle extracted from hops.

   2. The fine yellow resinous powder found upon the strobiles
      or fruit of hops, and containing this bitter principle.
      [Written also {lupuline}.]