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.
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.