1. A colorless volatile flammable liquid, C₂H₅OH, synthesized or obtained by fermentation of sugars and starches and widely used, either pure or denatured, as a solvent and in drugs, cleaning solutions, explosives, and intoxicating beverages. Also called ethanol, ethyl alcohol, Also called grain alcohol.
2. Intoxicating liquor containing alcohol.
3. Any of a series of hydroxyl compounds, the simplest of which are derived from saturated hydrocarbons, have the general formula C_nH_2n+1OH, and include ethanol and methanol.

[Medieval Latin, fine metallic powder, especially of antimony, from Arabic al-kuḥl : al-, the + kuḥl, powder of antimony.]

WORD HISTORY   The al- in alcohol may alert some readers to the fact that this is a word of Arabic descent, as is the case with algebra and alkali, al- being the Arabic definite article corresponding to the in English. The origin of -cohol is less obvious, however. Its Arabic ancestor was kuḥl, a fine powder most often made from antimony and used by women to darken their eyelids; in fact, kuḥl has given us the word kohl for such a preparation. Arabic chemists came to use al-kuḥl to mean "any fine powder produced in a number of ways, including the process of heating a substance to a gaseous state and then recooling it." The English word alcohol, derived through Medieval Latin from Arabic, is first recorded in 1543 in this sense. Arabic chemists also used al-kuḥl to refer to other substances such as essences that were obtained by distillation, a sense first found for English alcohol in 1672. One of these distilled essences, known as "alcohol of wine," is the constituent of fermented liquors that causes intoxication. This essence took over the term alcohol for itself, whence it has come to refer to the liquor that contains this essence as well as to a class of chemical compounds such as methanol.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.