1540s (early 15c. as alcofol), "fine powder produced by sublimation," from Medieval Latin alcohol "powdered ore of antimony," from Arabic al-kuhul "kohl," the fine metallic powder used to darken the eyelids, from kahala "to stain, paint." The al- is the Arabic definite article, "the."
Paracelsus (1493-1541) used the word to refer to a fine powder but also a volatile liquid. By 1670s it was being used in English for "any sublimated substance, the pure spirit of anything," including liquids.
The sense of "intoxicating ingredient in strong liquor" is attested by 1753, short for alcohol of wine, which then was extended to "the intoxicating element in fermented liquors." The formerly preferred terms for the substance were rectified spirits or brandy.
In organic chemistry, the word was extended by 1808 to the class of compounds of the same type as this (a 1790 translation of Lavoisier's "Elements of Chemistry" has alkoholic gas for "the combination of alkohol with caloric").
"disease of alcohol addiction," by 1882, from alcohol + -ism, or else from Modern Latin alcoholismus, coined in 1852 by Swedish professor of medicine Magnus Huss to mean what we now would call "alcohol poisoning, effects of excessive ingestion of alcohol." In earlier times, alcohol addiction would have been called habitual drunkenness or some such term.
first oxidation product of alcohol, 1833, discovered in 1774 by German-born Swedish chemist Carl Wilhelm Scheele, the name said to have been coined by German chemist Justus von Liebig from abbreviation of Modern Latin alcohol dehydrogenatum "dehydrogenated alcohol." Related: Aldehydic.