a mixture of amyl alcohols, propanol, and butanol: a by-product in the distillation of fermented liquors used as a source of amyl alcohols
Word origin
C19: from German Fusel bad spirits
fusel oil in American English
(ˈfjuzəl; ˈfjusəl)
an oily, acrid, poisonous liquid occurring in imperfectly distilled alcoholic products and consisting chiefly of amyl alcohols: small amounts contribute to the characteristic flavor of a whiskey