Vinegar is an acidic liquid processed from the fermentation of ethanol in a process that yields its key ingredient, acetic acid (also called ethanoic acid). It also may come in a diluted form. The acetic acid concentration typically ranges from 4 to 8 percent by volume for table vinegar (typically 5%) and higher concentrations for pickling (up to 18%). Natural vinegars also contain small amounts of tartaric acid, citric acid, and other acids. Vinegar has been used since ancient times and is an important element in Western, European, Asian, and other traditional cuisines of the world. The word "vinegar" derives from the Old French vin aigre, meaning "sour wine.". It also is known as acidity regulator E260. I would say therefore than vinegar is not an acid, but does contain one.