乙醇 (yǐ chún) is the formal scientific term for ethanol or ethyl alcohol — a volatile, flammable liquid commonly found in alcoholic beverages, disinfectants, and industrial solvents. The character 乙 (yǐ) is the second of the ten Heavenly Stems, historically used in chemical nomenclature to denote a two-carbon chain; 醇 (chún) means 'alcohol' in the chemical sense, referring specifically to organic compounds with a hydroxyl (–OH) group attached to a saturated carbon atom. Together, 乙醇 precisely identifies the simplest primary alcohol with formula C₂H₅OH.

This word is used primarily in medical, pharmaceutical, laboratory, and regulatory contexts — for example, on hand sanitizer labels, lab reports, or public health guidelines. It is more technical and formal than the colloquial term 酒精 (jiǔ jīng), which also means 'alcohol' but often refers broadly to drinking alcohol or rubbing alcohol in everyday speech. Learners should note that 乙醇 appears almost exclusively in written, scientific, or official language — rarely in casual conversation.