Alcohol: An organic chemical in which one or more hydroxyl (OH) groups are attached to carbon (C) atoms in place of hydrogen (H) atoms. Common alcohols include ethyl alcohol or ethanol (found in alcoholic beverages), methyl alcohol or methanol (can cause blindness) and propyl alcohol or propanol (used as a solvent and antiseptic). Rubbing alcohol is a mixture of acetone, methyl isobutyl ketone, and ethyl alcohol. In everyday talk, alcohol usually refers to ethanol as, for example, in wine, beer, and liquor. It can cause changes in behavior and be addictive.

The word "alcohol" has an unlikely origin. It came from the Arabic "al" (the) = "kuhl" (a fine impalpable powder) and referred originally to finely powdered antimony which women used to tint their eyelids.