means A strong distilled spirit made from sugarcane juice or molasses, typically aged in wooden casks and ranging from clear and sharp to dark and treacly.

from The word surfaces in 17th-century Caribbean colonies, where sugar plantations turned molasses into liquor. Its fuller early form was 'rumbullion' (also 'rumbustion'), a fine rowdy word of obscure origin — possibly slang for an uproar or commotion, which fits the drink that caused so many. The shortened 'rum' won out. There's a separate, older English 'rum' meaning 'fine' or 'excellent' (later twisting into 'odd' or 'strange'), and some have tried to link the two, but the connection is unproven and the spirit's name is best left as a genuine mystery born in the sugar islands.