1. Vegetable acid; an acid liquor obtained from wine, cider, beer or other liquors, by the second or acetous fermentation. Vinegar may differ indefinitely in the degree of its acidity. When highly concentrated, it is called radical vinegar.

2. Any thing really or metaphorically sour. [Not in use.]

Vinegar of lead, a liquor formed by digesting ceruse or litharge with a sufficient quantity of vinegar to dissolve it.