Sour liquid obtained by fermentation of dilute alcoholic liquids. Probably first made from wine (French vinaigre means sour wine), vinegar may also be made from malted barley, rice, cider, or other substances. The source substance, which must contain sugar, is fermented by yeast to produce alcohol. The alcohol is then aerated, which causes it to convert, through the action of Acetobacter bacteria, to acetic acid, water, and various other compounds. Vinegar is used in pickling meat, fish, fruits, and vegetables and in creating marinades, dressings, and other sauces.