vinegar made from wine by the agency of acetic acid bacteria, vinegar which is obtained exclusively by acetous fermentation of wine, and has a total acidity of not less than 60 grams per litre expressed as acetic acid, vinegar - sour liquid that is made by the fermentation of any of numerous dilute alcoholic liquids into a liquid containing acetic acid. Vinegar may be produced from a variety of materials: apples or grapes (wine or cider vinegar); malted barley or oats (malt vinegar); and industrial alcohol (distilled white vinegar). ... As a commercial product, however, vinegar was probably first made from wine (French vin, "wine"; aigre, "sour"). Vinegar can be made from any liquid that is capable of being converted into alcohol in a two-step process.