Acetic, a set'ic, Acid, an acid produced by the oxidation of common alcohol and of many other organic substances. Pure acetic acid has a very sour taste and pungent smell, burns the skin and is poisonous. Pure strong acetic acid is called glacial acetic acid and at temperatures below 62 deg. F. it is a solid. Vinegar is simply dilute acetic acid, and is prepared by exposing wine or weak spirits to the action of the air. It is also obtained from malt which has undergone fermentation. Acetic acid, both concentrated and dilute, is largely used in the arts, in medicine and for domestic purposes. See VINEGAR.