fusel oil
noun
fu·sel oil ˈfyü-zəl- 
: an acrid oily liquid occurring in insufficiently distilled alcoholic liquors, consisting chiefly of amyl alcohol, and used especially as a source of alcohols and as a solvent
Word History
Etymology
partial translation of German Fuselöl, from Fusel "distilled spirits of poor quality," probably originally in Low German dialects, of obscure origin
First Known Use
1850, in the meaning defined above
Medical Definition
fusel oil
noun
fu·sel oil ˈfyü-zəl-
: an acrid oily liquid occurring in insufficiently distilled alcoholic liquors, consisting chiefly of amyl alcohol, and used especially as a source of alcohols and as a solvent