a liquor or brew containing alcohol as the active agent
"alcohol (or drink) ruined him"
any of a series of volatile hydroxyl compounds that are made from hydrocarbons by distillation
"The chemist carefully monitored the still to ensure the distilled alcohol met the precise criteria for being a volatile hydroxyl compound derived directly from the hydrocarbon feedstock."
Any of a class of organic compounds (such as ethanol) containing a hydroxyl functional group (-OH).
"The chemist carefully synthesized a new alcohol to test its reactivity in the presence of strong oxidizing agents."
In plain English: Alcohol is a chemical substance that makes you feel relaxed and less aware of what's happening around you when you drink it.
"He decided to drink some alcohol after a long day at work."
Usage: In everyday conversation, alcohol refers specifically to ethyl alcohol or ethanol, the intoxicating ingredient found in beverages like beer and wine. While the scientific definition includes all organic compounds with a hydroxyl group, casual usage almost always points to this single type of drinkable substance.
The word alcohol entered English in the 15th century from French and Spanish versions of an Arabic term that originally meant "kohl," a cosmetic eye powder. Over time, the meaning broadened in medical literature to describe any fine powder or concentrated liquid obtained by boiling down substances.