Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula C₂H₆O. Its formula can also be written as CH₃−CH₂−OH or C₂H₅OH (an ethyl group linked to a hydroxyl group). Ethanol is a volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. It is a psychoactive recreational drug, and the active ingredient in alcoholic drinks.

Ethanol is naturally produced by the fermentation process of sugars by yeasts or via petrochemical processes such as ethylene hydration. Historically it was used as a general anesthetic, and has modern medical applications as an antiseptic, disinfectant, solvent for some medications, and antidote for methanol poisoning and ethylene glycol poisoning. It is used as a chemical solvent and in the synthesis of organic compounds, and as a fuel source. Ethanol also can be dehydrated to make ethylene, an important chemical feedstock. As of 2006, world production of ethanol was 51 gigalitres (1.3×10¹⁰ US gallons), coming mostly from Brazil and the U.S.