The Collaborative International Dictionary of English v.0.48:

Rum \Rum\, n. [probably shortened from Prov. E. rumbullion a
   great tumult, formerly applied in the island of Barbadoes to
   an intoxicating liquor.]
   A kind of intoxicating liquor distilled from cane juice, or
   from the scummings of the boiled juice, or from treacle or
   molasses, or from the lees of former distillations. Also,
   sometimes used colloquially as a generic or a collective name
   for intoxicating liquor.
   [1913 Webster]

   Rum bud, a grog blossom. [Colloq.]

   Rum shrub, a drink composed of rum, water, sugar, and lime
      juice or lemon juice, with some flavoring extract.
      [1913 Webster]