1. A colorless, volatile, pungent liquid; synthesized or derived from fermentation of sugars and starches: Alcohol can be burned as fuel, is used in industry and medicine, and is the intoxicating element of whiskey, wine, beer, and other fermented or distilled liquors. It is also called "ethyl alcohol".
2. Any of a series of hydroxyl compounds: The simplest kind of alchol is derived from saturated hydrocarbons, and includes ethanol and methanol.